Design and synthesis of bichromophores for nonlinear optical applications in polymer films

Article abstract of DOI:10.1016/j.reactfunctpolym.2011.01.009

Three bichromophores were designed and synthesized by linking a vinylthiophene-conjugated chromophore with different tether groups via esterification. Second harmonic generation measurements of nonlinear polymer films revealed that the second harmonic gen

Full text of DOI:10.1016/j.reactfunctpolym.2011.01.009

Reactive & Functional Polymers 71 (2011) 496–501
Contents lists available at ScienceDirect
Reactive & Functional Polymers
journal homepage: www.elsevier.com/locate/react
Design and synthesis of bichromophores for nonlinear optical applications
in polymer films
⇑
⇑
Junkuo Gao, Yuanjing Cui , Jiancan Yu, Wenxin Lin, Zhiyu Wang, Guodong Qian
State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Three bichromophores were designed and synthesized by linking a vinylthiophene-conjugated chromo-
phore with different tether groups via esterification. Second harmonic generation measurements of non-
linear polymer films revealed that the second harmonic generation coefficients of the films containing the
bichromophore and using 3-phenoxypropane-1,2-diyl succinic diester as the tether group were improved
in comparison with the mono-chromophore-doped polymer films. However, the second harmonic gener-
ation coefficients of the polymer films containing bichromophores using isophthalic ester as the tether
group were decreased. Overall, the results indicate that the 3-phenoxypropane-1,2-diyl succinic diester
tether group has potential applications in the design and synthesis of multi-chromophoric dendrimers
with large macroscopic optical nonlinearity.
Received 8 November 2010
Received in revised form 19 January 2011
Accepted 19 January 2011
Available online 24 January 2011
Keywords:
Bichromophore
Nonlinear optics
Tether groups
Second harmonic generation
Polymer film
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
Inthisstudy, wedesignedandsynthesizedthree bichromophores
by choosing tether groups with different electronic enrichments,
Organic nonlinear optical (NLO) materials have drawn
considerable attention over the past two decades due to their poten-
tial applications in photonic devices [1–6]. Poled polymers that
incorporate chromophores with high hyperpolarizabilities b into
their polymeric host matrices and are poled by an electrical field to
obtain a noncentrosymmetric arrangement are the most widely
studied organic NLO materials [7–11]. Unfortunately, the strong di-
pole–dipole interactions between chromophores have led to unfa-
vorable, antiparallel packing of the chromophores, making the
conversion from the high b values of the chromophores to large mac-
roscopic optical nonlinearities a continual challenge [12–15].
In recent years, multi-chromophores synthesized by linking
mono-chromophores via tether groups have become widely stud-
ied [16–18]. It has been reported that multi-chromophores exhibit
a much higher figure of merit than their corresponding mono-
chromophores [19–22]. Generally, multi-chromophores are syn-
thesized by linking NLO chromophores with different tether
groups, and the tether groups, in turn, greatly affect the electro-
optic properties of the multi-chromophores [23]. In other words,
the tether groups have been found to play an important role in
the formation of multi-chromophores but require further study
to determine which tether groups can improve the macroscopic
optical nonlinearities [24].
lengths and flexibilities. Additionally, we systemically studied their
optical nonlinearities in a polymer matrix. In this approach, a com-
mon thiophene containing FTC-type chromophore [25,26], was cho-
sen as the mono-chromophore unit for construction of all of the
bichromophores; it has a large b value and is a robust compound.
In addition, esterification was used in the design and synthesis of
the multi-chromophores and the NLO polymer materials because
of its synthetic convenience and high yield [27,28]. The bichromo-
phores studied were synthesized via esterification between the link-
ing groups and the FTC chromophore. Furthermore, the macroscopic
optical nonlinearities of the bichromophores and FTC chromophore-
doped poly(4-vinylphenol) (PVPh) thin films were studied to evalu-
ate the differences in the bichromophores with different tether
groups. Our goal in this study was to search for tether groups that
could enhance the macroscopic optical nonlinearity.
2. Experimental
2.1. Materials and measurements
All chemicals were purchased from Alfa Aesar and Aldrich and
used as received. Dichloromethane and N,N-dimethylformamide
(DMF) were distilled over drying agents before use. Isophthalic
acid was commercially available and used without further purifica-
tion. Chromophore FTC1 and 5-(trimethylsilyloxy)isophthalic acid
(compound 2) were prepared according to procedures found in the
literature [26,29].
⇑
Corresponding authors. Tel.: +86 571 87952334; fax: +86 571 87951234.
E-mail addresses: cuiyj@zju.edu.cn (Y. Cui), gdqian@zju.edu.cn (G. Qian).
1381-5148/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.reactfunctpolym.2011.01.009

J. Gao et al. / Reactive & Functional Polymers 71 (2011) 496–501
497
1H and 13C NMR spectra were collected on a Bruker Avance
2.2.3. Synthesis of B2
DMX500 spectrometer. Mass spectrometry was performed on a
Bruker Daltonics Esquire3000plus mass spectrometer. UV–visible
absorption spectra were obtained using a Perkin-Elmer Lambda
20 spectrophotometer. Elemental analyses were obtained from a
ThermoFinnigan Instruments Flash EA1112 microelemental ana-
lyzer. Thermogravimetric analysis (TGA) was performed using a
TA Instruments SDT Q600 at a heating rate of 10 °C minÀ1 and un-
der a nitrogen atmosphere. Differential scanning calorimetry (DSC)
was performed in a nitrogen atmosphere using a Netzsch Instru-
ments 200 F3 with a heating rate of 10 °C minÀ1; the DSC thermo-
grams of the bichromophores were obtained from the second scan.
Film thicknesses were measured using a Tencor Alfa-Step 200 sur-
face profilometer. The second harmonic generation (SHG) coeffi-
cient (d33) of the poled film was measured using a Q-switched
Nd:YAG laser at 1064 nm and a Y-cut quartz crystal (d11 = 0.5
pm VÀ1) as the Refs. [30,31].
Compound 2 (0.15 g, 0.5 mmol) and FTC1 (0.47 g, 1.0 mmol)
were dissolved in CH2Cl2 (60 mL), and the reaction mixture was
cooled to 0 °C. Next, DCC (0.24 g, 1.2 mmol) and DMAP (0.14 g,
1.2 mmol) were added to the mixture, and the solvent was warmed
to room temperature and stirred for 24 h. After that time, the solu-
tion was diluted with CH2Cl2 (100 mL) and washed with brine and
DI water. The organic phase was dried over MgSO4, and the solvent
was removed under reduced pressure. The product was obtained
by silica column chromatography using 10% ethyl acetate in CH2Cl2
as the eluent. Yield: 68%. 1H NMR (500 MHz, DMSO-d6, d ppm):
0.18 (s, 6H, Si(CH3)2), 0.94 (t, 9H, C(CH3)3), 1.78 (s, 12H, C(CH3)2),
3.00 (s, 6H, NCH3), 3.79 (s, 4H, NCH2), 4.47 (t, 4H, OCH2), 6.62
(d, J = 16 Hz, 2H, CH = CH), 6.77 (d, J = 9 Hz, 4H, ArH), 7.14–7.23
(m, 6H, ArH, CH = CH), 7.41 (d, J = 8.6 Hz, 4H, ArH), 7.48 (d,
J = 8.8 Hz, 2H, ArH), 7.73 (d, J = 8.8 Hz, 2H, ArH), 7.96 (s, 1H, ArH),
8.11 (d, J = 16 Hz, 2H, CH = CH). 13C NMR (125 MHz, DMSO-d6, d
ppm): 177.213, 174.876, 165.069, 155.815, 153.685, 150.146,
140.871, 139.314, 138.165, 134.497, 131.983, 129.231, 128.127,
125.131, 124.145, 123.440, 116.700, 113.471, 112.718, 112.491,
112.340, 111.637, 98.987, 96.920, 63.236, 60.233, 53.323, 50.361,
38.548, 26.048, 25.906, 18.382, 14.562, -4.219. Elemental analysis
calcd (%) for C68H64N8O7S2Si: C, 68.20; H, 5.39; N, 9.36. Found: C,
68.27; H, 5.35; N, 9.44. MS (ESI): exact mass calcd for
2.2. Synthesis
2.2.1. Synthesis of compound 3
To a solution of 3-phenoxypropane-1,2-diol (1.68 g, 10 mmol)
and succinic anhydride (2.2 g, 22 mmol) in anhydrous dichloro-
methane (50 mL), DMAP (0.90 g) and pyridine (1.5 mL) were
added. The reaction mixture was stirred at room temperature over-
night, and the following day, the mixture was washed with brine
and DI water for three times. The organic phase was dried over
MgSO4, and the solvent was removed under reduced pressure.
The residue was purified by silica column chromatography using
50% ethyl acetate in CH2Cl2 as the eluent to give the final product.
Yield: 65%. 1H NMR (500 MHz, CDCl3, d ppm): 2.65 (m, 8H, COCH2),
4.11 (q, J = 6.2 Hz, 2H, CCH2O), 4.35 (d, J = 8.8 Hz, 1H, higher field
branch of AB quartet, ArOCH2), 4.48 (d, J = 6 Hz, 1H, lower field
branch of AB quartet, ArOCH2), 5.41 (m, 1H, CHCH2), 6.88
(d, J = 8 Hz, 2H, ArH), 6.96 (t, 1H, ArH), 7.27 (d, J = 8 Hz, 2H, ArH),
9.82 (s, 2H, COOH). Elemental analysis calcd (%) for C17H20O9: C,
55.43; H, 5.47. Found: C, 55.69; H, 5.63. MS (ESI): exact mass calcd
for C17H20O9 [M–H]À, 367.1. Found: 367.0.
C
68H64N8O7S2Si [M–H]À, 1195.4. Found: 1195.7.
2.2.4. Synthesis of B3
Reaction of compound 3 with FTC1 was performed as described
for B1, except with subsequent purification by silica column chro-
matography using 8% ethyl acetate in CH2Cl2 as the eluent. Yield:
72%. 1H NMR (500 MHz, DMSO-d6, d ppm): 1.79 (s, 12H, C(CH3)2),
2.63 (m, 8H, COCH2), 3.31 (s, 6H, NCH3), 3.61 (s, 4H, NCH2), 4.11
(d, 2H, CCH2O), 4.16 (t, 4H, OCH2), 4.28(d, J = 4.6 Hz, 2H, ArOCH2),
5.28(s, 1H, CHCH2), 6.63 (d, J = 16 Hz, 2H, CH = CH), 6.73 (d,
J = 8.8 Hz, 4H, ArH), 6.93 (m, 4H, ArH), 7.16 (d, J = 15.7 Hz, 2H,
CH = CH), 7.23–7.28 (m, 6H, ArH), 7.46 (d, J = 8.8 Hz, 4H, ArH),
7.73 (d, J = 8.8 Hz, 2H, ArH), 8.08 (d, J = 16 Hz, 2H, CH = CH). 13C
NMR (125 MHz, DMSO-d6, d ppm): 177.238, 174.889, 172.302,
172.219, 172.092, 171.884, 158.481, 153.728, 149.933, 140.866,
139.296, 138.166, 134.521, 130.006, 129.247, 128.153, 124.160,
121.568, 116.763, 115.074, 113.481, 112.723, 112.398, 112.342,
111.661, 98.998, 96.884, 70.167, 66.430, 62.642, 61.947, 53.310,
50.412, 38.807, 29.056, 28.904, 26.042. Elemental analysis calcd
(%) for C71H64N8O11S2: C, 67.18; H, 5.08; N, 8.83. Found: C, 66.70;
H, 5.24; N, 8.48. MS (ESI): exact mass calcd for C71H64N8O11S2
[M–H]À, 1267.4. Found: 1266.7.
2.2.2. Synthesis of bichromophore B1
A solution of chromophore FTC1 (1.03 g, 2.2 mmol) and iso-
phthalic acid (0.17 g, 1 mmol) in anhydrous dichloromethane
(60 mL) and DMF (0.5 mL) was stirred for 10 min at room temper-
ature. Next, the mixture was cooled to 0 °C in an ice bath, and
DMAP (0.54 g, 4.4 mmol) and EDC.HCl (1.26 g, 6.6 mmol) were
added to the mixture. Once the additions were complete, the ice
bath was removed, and the reaction mixture was stirred at room
temperature for 24 h. After that time, the mixture was diluted with
CH2Cl2 (120 mL) and washed with brine and DI water. The organic
phase was dried over MgSO4, and the solvent was evaporated un-
der reduced pressure. The product was obtained by silica column
chromatography using 10% ethyl acetate in CH2Cl2 as the eluent.
Yield: 61%. 1H NMR (500 MHz, DMSO-d6, d ppm): 1.83 (s, 12H,
C(CH3)2), 3.05 (s, 6H, NCH3), 3.85 (t, 4H, NCH2), 4.52 (t, 4H,
OCH2), 6.67 (d, J = 16 Hz, 2H, CH = CH), 6.83 (d, 4H, ArH), 7.17–
7.29 (m, 6H, ArH, CH = CH), 7.48 (d, J = 8.9 Hz, 4H, ArH), 7.66
(t, 1H, ArH), 7.77 (d, J = 8.8 Hz, 2H, ArH), 8.12–8.15 (m, 4H, ArH,
CH = CH), 8.38 (s, 1H, ArH). 13C NMR (125 MHz, DMSO-d6, d
ppm): 177.222, 174.870, 165.357, 153.679, 150.136, 140.862,
139.291, 138.153, 134.487, 134.136, 130.474, 130.103, 129.814,
129.220, 128.137, 124.187, 116.736, 113.455, 112.702, 112.549,
112.334, 111.639, 98.986, 96.894, 63.039, 53.290, 50.426, 38.654,
26.026. Elemental analysis calcd (%) for C62H50N8O6S2: C, 69.77;
H, 4.72; N, 10.50. Found: C, 69.88; H, 4.93; N, 10.29. MS (ESI): exact
mass calcd for C62H50N8O6S2 [M], 1066.3. Found: 1066.9.
2.3. Thin film fabrication
Each chromophore was mixed with solid PVPh, and the solid
components were dissolved into cyclopentanone (8% of total solid
weight), stirred in a vial for 1 h, filtered through 0.22-lm Teflon
membrane filters and spin-coated onto indium-tin oxide (ITO)
glass substrates. Once the coatings were complete, the films were
dried in a vacuum oven at 85 °C for 12 h to remove the residual
solvent.
3. Results and discussion
3.1. Synthesis and characterization
Structures of the bichromophores are shown in Fig. 1, and all of
the bichromophores were synthesized via esterification between
the linking groups and FTC chromophore. The first linking group
synthesized, compound 2, was specifically designed to introduce

498
J. Gao et al. / Reactive & Functional Polymers 71 (2011) 496–501
Fig. 1. Structures of FTC1 and the bichromophores.
an electron-rich group, tert-butyldimethylsilyloxy, to the 5-posi-
tion of isophthalic acid and was produced by a protection and
deprotection procedure with 5-hydroxyisophthalic acid, as shown
in Scheme 1. Interestingly, isophthalic acid and its derivative, com-
pound 2, are widely used as linking groups in the synthesis of den-
drimers [19,32]. Another linking group we synthesized was formed
by reacting 3-phenoxypropane-1,2-diol with succinic anhydride to
produce a carboxylic acid functionalized compound 3. Applications
of this long, flexible linking group in multi-chromophore and
dendrimer syntheses have not been reported in the literature.
The overall synthetic route of the bichromophores is shown in
Scheme 2. Here, bichromophore B1 was based on the isophthalic
acid linking group, where esterification between isophthalic acid
and chromophore FTC1 produced a relatively short, inflexible
isophthalic ester tether group. The reaction between 2 and FTC1
yielded B2 with 5-(tert-butyldimethylsilyloxy)isophthalic ester as
the tether group. In bichromophore B3, 3-phenoxypropane-1,2-
diyl succinic diester was used as a long, flexible tether group.
The structures of the bichromophores were confirmed by elemen-
tal analysis, 1H NMR, 13C NMR and mass spectrometry. The details
of the syntheses and characterizations are provided in the
Experimental Section.
Thermal properties of FTC1, B1, B2 and B3 were explored by
DSC and TGA, as shown in Figs. 2 and 3. Compound FTC1 displayed
a melting point (Tm) of 250 °C, whereas all of the bichromophores
showed a range of glass transition temperatures (Tg) instead of
melting points. The Tg of compound B1 was 135 °C, and for B2,
the Tg was 130 °C, which was 5 °C lower than that of B1. The differ-
ence in the temperatures was attributed to the introduction of the
flexible tert-butyldimethylsilyloxy group in compound B2. Com-
pound B3 showed the lowest Tg, which was 93 °C, resulting from
the longer, more flexible 3-phenoxypropane-1,2-diyl succinic dies-
ter tether group. The decomposition temperature (Td) of FTC1 was
found to be 258 °C; however, all of the bichromophores showed
much higher Td than FTC1. Compound B2 gave the highest Td,
which was 32 °C higher than that of FTC1. The Td of compound
Scheme 1. Syntheses of compounds 2 and 3.

J. Gao et al. / Reactive & Functional Polymers 71 (2011) 496–501
499
Scheme 2. Synthesis of bichromophore B1.
absorption spectra of FTC1 and the bichromophores in CHCl3 are
shown in Fig. 4. Chromophore FTC1 showed a maximum absorp-
tion wavelength (kmax) of 644 nm in CHCl3. However, the maxi-
mum absorption wavelengths (kmax) of bichromophore B1, B2
and B3 in CHCl3 were 634 nm, 636 nm and 639 nm, respectively.
Small blue shifts were observed for all of the bichromophores com-
pared with mono-chromophore FTC1. Specifically, the kmax of the
isophthalic ester tether group attached to B1 displayed the largest
blue shift, approximately 10 nm. This shift was mainly attributed
to the electron-withdrawing inductive effect of the ester group,
which reduced the electron-donating ability of the amine donor
site of the FTC1 mono-chromophore [23,32]. The detrimental
reduction of electron density to the donor site decreased the intra-
molecular charge transfer band, which, in turn, led to the hypso-
chromic shift [33]. The blue shift of kmax was also influenced by
the inter-chromophore interaction between the sub-chromophores
of the bichromophores, as reported in the literature [34,13]. The
kmax of B2 showed a blue shift of 8 nm, which was smaller than
that of B1. Compared with the isophthalic ester tether group in
B1, the 5-(tert-butyldimethylsilyloxy)isophthalic ester tether
group in B2 contained an electron-rich tert-butyldimethylsilyloxy
group. In other words, the electron-donating conjugation of the
tert-butyldimethylsilyloxy group via the phenyl decreased the
polarity of the ester group, which reduced the detrimental effect
the ester group played on the amine donor and resulted in a smal-
ler blue shift. The smallest blue shift (5 nm) was observed for the
kmax of B3, indicating that the 3-phenoxypropane-1,2-diyl succinic
Fig. 2. DSC thermograms of compound FTC1, B1, B2 and B3: (a) FTC1, (b) B3, (c) B2
and (d) B1.
Fig. 3. TGA curves of FTC1 and the bichromophores: (a) FTC1, (b) B1, (c) B2 and (d)
B3.
B1 and B3 showed less improvement, 27 °C and 21 °C, compared
with that of FTC1, indicating that the molecular thermal stability
could be efficiently improved in the bichromophores that were
more suitable for photonic device fabrications.
3.2. Linear and nonlinear optical properties
The linear optical properties of the bichromophores were stud-
ied by UV–visible absorption spectroscopy. The UV–visible
Fig. 4. UV–visible absorption spectra of FTC1 and the bichromophores in CHCl3.

500
J. Gao et al. / Reactive & Functional Polymers 71 (2011) 496–501
Table 1
diester tether group was able to minimize the detrimental influ-
ence of the ester on the electron-donating ability of the donor site.
NLO thin films containing FTC1 and the bichromophores were
prepared by choosing PVPh as the polymer matrix [35]. Due to
the poor solubility of B1 in the organic solvents, only a doping level
of 10 wt.% was achieved. The doping levels of the other three com-
pounds were only able to reach 20 wt.% without phase separation.
The bichromophore doped polymer films were fabricated and com-
pared with the FTC1-doped polymer films with the same doping
level because the active chromophore units were almost equal
when using the same loading densities. Generally, the thickness
of the films was in the range of 500–600 nm. The second-order
NLO properties of the polymer films were characterized by their
SHG measurements using the Maker fringe technique [36,37].
The second harmonic coefficient (d33) of the film can be calculated
by comparing the film’s SHG with the SHG intensity of a standard
Y-cut quartz crystal plate. In this case, the films were poled by
applying a 6-kV dc voltage at 140 °C for 1 h; the d33 values of the
films are shown in Fig. 5. When the chromophore doping level
was 10 wt.%, the d33 value of the films containing B1 (film-B1)
was 12 pm VÀ1; however, the d33 values of films containing B2
Wavelength of maximum absorption (kmax) and maximum second harmonic coeffi-
cients of the NLO thin films.
Films
kmax (nm)
u
d33 (pm VÀ1
)
d33(0) (pm VÀ1
)
Film-FTC1
Film-B2
Film-B3
656
654
651
0.11
0.10
0.18
32
24
42
10
7
13
comparison with the isophthalic ester tether group, 3-phenoxypro-
pane-1,2-diyl succinic diester created a long and flexible structure
that allowed the mono-chromophores to rotate freely in the pres-
ence of the poling field, thus increasing the poling order and the d33
values [23]. Overall, the results indicated that the inflexible
isophthalic ester tether group decreased the macroscopic optical
nonlinearities, and the longer and flexible 3-phenoxypropane-
1,2-diyl succinic diester tether group improved the optical
nonlinearities. Additionally, with proper modification, the 3-phen-
oxypropane-1,2-diyl succinic diester could be used in the synthe-
ses of multi-chromophore dendrimers for enhanced optical
nonlinearities; this work is now in progress.
The thermal dynamic stabilities of the poled films were also
investigated through a depoling experiment in which the temper-
ature was ramped at a rate of 10 °C minÀ1, as shown in Fig. 6. The
half-decay temperatures determined for the d33 values of film-
FTC1 and film-B2 (20 wt.%) were about 125 °C and 116 °C, respec-
tively, whereas the d33 signal of film-B3 (20 wt.%) was stable at
80 °C. In contrast, the signal of film-B3 then decayed rapidly with
the further increase of temperature and almost disappeared when
heating to 100 °C. This result could be attributed to the low Tg of
bichromophore B3, which was about 93 °C. In addition, due to
the much higher Tg of bichromophore B2, the half-decay tempera-
ture of the d33 values for film-B2 was 28 °C higher than that for
film-B3 (88 °C). Therefore, the results indicate that improvement
of the Tg for the multi-chromophores could enhance the thermal
stability of the poled films.
(film-B2), B3 (film-B3) and FTC1 (film-FTC1) were 17 pm VÀ1
,
26 pm VÀ1 and 23 pm VÀ1, respectively. Film-B1 and film-B2
showed reduced d33 values compared to that of film-FTC1 with
the same doping level; moreover, the d33 value of film-B1 was
the smallest, only half that of film-FTC1. The reason for the de-
crease in the d33 values for film-B1 and film-B2 could be attributed
to the inflexible and short isophthalic ester tether group that made
the mono-chromophores difficult to rotate under the poling field.
On the other hand, for film-B3, the largest d33 value was 42 pm VÀ1
(20 wt.%), which was an improvement in comparison with film-
FTC1 (20 wt.%). The largest d33 value of film-FTC1 that was
achieved was 32 pm VÀ1 (20 wt.%), and the largest d33 value of
film-B2 was 24 pm VÀ1 (20 wt.%).
To correct for the absorptions that could lead to resonance
enhancement of the SHG, the nonresonant d33(0) values of the
NLO thin films were obtained by using the approximate two-level
model and are summarized in Table 1 [38,39]. The maximum
d33(0) values of film-FTC1 and film-B2 were determined to be
10 pm VÀ1 and 7 pm VÀ1, respectively. However, film-B3 displayed
a d33(0) value of 13 pm VÀ1, which was higher than the maximum
d33(0) values of film-FTC1 and film-B2. To characterize the poling
4. Conclusions
A series of bichromophores were synthesized by attaching dif-
ferent tether groups with a vinylthiophene-conjugated FTC-type
chromophore, and their NLO activities in a polymeric matrix were
studied and compared. The results indicated that the inflexible
isophthalic ester tether group in B1 and B2 reduced the d33 value
of the NLO polymer films. However, the polymer films containing
bichromophore B3, with its longer, flexible 3-phenoxypropane-1,
2-diyl succinic diester tether group, displayed a d33 value of
efficiency of the polymer films, the order parameter
A0, where A0 and A1 are the absorbances of the film before and after
poling) was also calculated and tabulated in Table 1. The values
u
(u
= 1 À A1/
u
of film-FTC1, film-B2 and film-B3 at 20 wt.% were 0.11, 0.10 and
0.18, respectively. Once again, the bichromophore B3 doped poly-
mer films showed a much higher value than the other films. In
Fig. 5. d33 values of the polymer films as a function of chromophore loading
densities: (a) film-B3, (b) film-FTC1, (c) film-B2 and (d) film-B1.
Fig. 6. Decay of the normalized d33 values as a function of temperature for film-B2,
film-B3 and film-FTC1 at 20 wt.% and poled at 140 °C for 30 min.

J. Gao et al. / Reactive & Functional Polymers 71 (2011) 496–501
501
42 pm VÀ1, which was larger than that of the films containing
FTC1. Based on the improvement in optical nonlinearity made with
the 3-phenoxypropane-1,2-diyl succinic diester, potential applica-
tions in the design and synthesis of multi-chromophoric dendri-
mers with quite large macroscopic optical nonlinearity are
possible.
[16] A. Datta, F. Terenziani, A. Painelli, Chem. Phys. Chem. 7 (2006) 2168–2174.
[17] Y. Liao, K.A. Firestone, S. Bhattacharjee, J.D. Luo, M. Haller, S. Hau, C.A.
Anderson, D. Lao, B.E. Eichinger, B.H. Robinson, P.J. Reid, A.K.Y. Jen, L.R. Dalton,
J. Phys. Chem. B 110 (2006) 5434–5438.
[18] J.K. Gao, Y.J. Cui, J.C. Yu, Z.Y. Wang, M.Q. Wang, J.R. Qiu, G.D. Qian,
Macromolecules 42 (2009) 2198–2203.
[19] M.J. Cho, D.H. Choi, P.A. Sullivan, A.J.P. Akelaitis, L.R. Dalton, Prog. Polym. Sci.
33 (2008) 1013–1058.
[20] P.A. Sullivan, H. Rommel, Y. Liao, B.C. Olbricht, A.J.P. Akelaitis, K.A.
Firestone, J.W. Kang, J.D. Luo, J.A. Davies, D.H. Choi, B.E. Eichinger, P.J.
Reid, A.T. Chen, A.K.Y. Jen, B.H. Robinson, L.R. Dalton, J. Am. Chem. Soc.
129 (2007) 7523–7530.
[21] J.D. Luo, M. Haller, H. Ma, S. Liu, T.D. Kim, Y.Q. Tian, B.Q. Chen, S.H. Jang, L.R.
Dalton, A.K.Y. Jen, J. Phys. Chem. B 108 (2004) 8523–8530.
[22] R. Paspirgelyte, J.V. Grazulevicius, S. Grigalevicius, V. Jankauskas, React. Funct.
Polym. 69 (2009) 183–188.
Acknowledgments
This work was financially supported by the National Natural
Science Foundation of China (Nos. 50802084, 50972127 and
51010002) and the Science and Technology Planning Project of
Zhejiang Province (No. 2009C32002).
[23] P.A. Sullivan, A.J.P. Akelaitis, S.K. Lee, G. McGrew, S.K. Lee, D.H. Choi, L.R.
Dalton, Chem. Mater. 18 (2006) 344–351.
[24] J. Holtmann, E. Walczuk, M. Dede, C. Wittenburg, J. Heck, G. Archetti, R.
Wortmann, H.G. Kuball, Y.H. Wang, K. Liu, Y. Luo, J. Phys. Chem. B 112 (2008)
14751–14761.
[25] J.D. Luo, S. Liu, M. Haller, L. Liu, H. Ma, A.K.Y. Jen, Adv. Mater. 14 (2002) 1763–
1768.
[26] D. Briers, G. Koeckelberghs, I. Picard, T. Verbiest, A. Persoons, C. Samyn,
Macromol. Rapid Commun. 24 (2003) 841–846.
[27] A. Scarpaci, E. Blart, V. Montembault, L. Fontaine, V. Rodriguez, F. Odobel,
Chem. Commun. (2009) 1825–1827.
[28] M. Faccini, M. Balakrishnan, R. Torosantucci, A. Driessen, D.N. Reinhoudt, W.
Verboom, Macromolecules 41 (2008) 8320–8323.
[29] E.R. Zubarev, S.I. Stupp, J. Am. Chem. Soc. 124 (2002) 5762–5773.
[30] Y.J. Cui, M.Q. Wang, L.J. Chen, G.D. Qian, Dyes Pigment. 65 (2005) 61–66.
[31] Y.J. Cui, M.Q. Wang, L.J. Chen, G.D. Qian, Dyes Pigment. 62 (2004)
43–47.
References
[1] L.R. Dalton, P.A. Sullivan, D.H. Bale, Chem. Rev. 110 (2010) 25–55.
[2] S.R. Marder, B. Kippelen, A.K.Y. Jen, N. Peyghambarian, Nature 388 (1997) 845–
851.
[3] A. Marrocchi, A. Spalletti, S. Ciorba, M. Seri, F. Elisei, A. Taticchi, J. Photochem.
Photobiol. A-Chem. 211 (2010) 162–169.
[4] L. Beverina, M. Crippa, M. Landenna, R. Ruffo, P. Salice, F. Silvestri, S. Versari, A.
Villa, L. Ciaffoni, E. Collini, C. Ferrante, S. Bradamante, C.M. Mari, R. Bozio, G.A.
Pagani, J. Am. Chem. Soc. 130 (2008) 1894–1902.
[5] S.K. Park, J.Y. Do, J.J. Ju, S. Park, M.-s. Kim, M.-H. Lee, React. Funct. Polym. 66
(2006) 974–983.
[6] J. Lukstaite, D. Gudeika, J.V. Grazulevicius, S. Grigalevicius, B. Zhang, Z. Xie,
React. Funct. Polym. 70 (2010) 572–577.
[7] K.A. Firestone, P. Reid, R. Lawson, S.H. Jang, L.R. Dalton, Inorg. Chim. Acta 357
(2004) 3957–3966.
[32] F. Terenziani, O. Mongin, C. Katan, B.K.G. Bhatthula, M. Blanchard-Desce,
Chem. Eur. J. 12 (2006) 3089–3102.
[8] W.J. Kuo, G.H. Hsiue, R.J. Jeng, Macromolecules 34 (2001) 2373–2384.
[9] K. Noniewicz, Z.K. Brzozowski, React. Funct. Polym. 33 (1997) 343–349.
[10] J. Hao, M.-J. Han, Y. Yang, Y. Shen, L. Qiu, X. Meng, Q. Shen, Z. Cao, React. Funct.
Polym. 66 (2006) 832–839.
[11] K.H. Park, M.G. Kwak, W.S. Jahng, C.J. Lee, N. Kim, React. Funct. Polym. 40
(1999) 41–49.
[12] B.H. Robinson, L.R. Dalton, J. Phys. Chem. A 104 (2000) 4785–4795.
[13] G.C. Bazan, J. Org. Chem. 72 (2007) 8615–8635.
[14] J.C. Yu, Y.J. Cui, J.K. Gao, Z.Y. Wang, G.D. Qian, J. Phys. Chem. B 113 (2009)
14877–14883.
[33] M.M.M. Raposo, A. Ferreira, M.M.F. Pereira, M. Belsley, J. Moura, Dyes Pigment.
83 (2009) 59–65.
[34] F. Terenziani, G. D’Avino, A. Painelli, ChemPhysChem 8 (2007) 2433–2444.
[35] A. Priimagi, M. Kaivola, F.J. Rodriguez, M. Kauranen, Appl. Phys. Lett. 90 (2007)
121103.
[36] W.N. Herman, L.M. Hayden, J. Opt. Soc. Am. B 12 (1995) 416–428.
[37] P.D. Maker, R.W. Terhune, M. Nisenoff, C.M. Savage, Phys. Rev. Lett. 8 (1962)
21–22.
[38] J.L. Oudar, J. Chem. Phys. 67 (1977) 446–457.
[39] M. Kauranen, T. Verbiest, C. Boutton, M.N. Teerenstra, K. Clays, A.J. Schouten,
R.J.M. Nolte, A. Persoons, Science 270 (1995) 966–969.
[15] J. Hao, M.-J. Han, K. Guo, J. Zhai, T. Zhang, X. Meng, J. Liang, L. Qiu, Y. Shen,
React. Funct. Polym. 67 (2007) 758–768.