Synthesis and optical storage properties of a thiophene-based holographic recording medium
The results of the fabrication and optical data storage characteristics of a novel azothiophene polyester 9 for potential holographic storage are reported. The polyester is derived from an azothiophene diol 1 and diphenyl phthalate 8 via in vacuo melt transesterification. Inclusion of a 5-methoxy-2-thienyl moiety generates a trans π-π* transition centered close to 405 nm. An investigation of the optical data storage characteristics of a solution cast film of azopolyester with a thickness of 65 m is summarised. The optical anisotropy induced by a 532 nm frequency doubled YAG laser and probed at a wavelength of 633 nm outside the absorption band with a polarimeter reveals a very high induced anisotropy of 7 rad (laser intensity, 250 mW cm-2). The calculated birefringence of the film is 0.02 per micron. Maximum anisotropy is reached after approximately 70 s of irradiation. The induced anisotropy disappears at approximately 90 °C. Room temperature stable gratings can be inscribed with high diffraction efficiency. The Royal Society of Chemistry 2007.
Matharu, Avtar S.,Jeeva, Shehzad,Huddleston, Patrick R.,Ramanujam
p. 4477 - 4482
(2008/12/22)
A novel one-pot synthesis of esters by exchange reactions between carbonates and anhydrides
A new method for the synthesis of esters by exchange reaction between anhydrides and carbonates, without any solvent, in the presence of Ti or Sn based catalyst is presented.
Berti, Corrado,Colonna, Martino,Marianucci, Elisabetta,Sweileh, Bassam,Pilati, Francesco
p. 917 - 927
(2007/10/03)
Purification of diphenyl phthalates
Color properties of crude phenolic esters of aromatic dicarboxylic acids are improved by subjecting the esters to hydrogenation in the presence of hydrogen and a hydrogenation catalyst.