Photochemical Image Storage in Polymer Liquid Crystals

Article abstract of DOI:10.1246/cl.1988.1679

Amplified optical image storage has been demonstrated in polymer liquid crystals (PLC).A small amount (< 5 molpercent) of a low molecular weight mesogen with a photoresponsive moiety, 4-butyl-4'-methoxyazobenzene (BMAB), was doped in the films of polyacrylates with mesogenic side chain, poly(4'-methoxyphenyl-4-acryloyloxyalkoxybenzoate) (PAn), in which the alkyl spacer length (CH2)_n was varied as n = 2, 3, 5, and 6.Photoirradiation of the PA3/BMAB film with a 366 nm light caused trans -> cis isomerization of BMAB, which induced simoltaneously the nematic (N) -> isotropic phase transition of the PLC films.This photochemically induced phase transition was reversible and photoirradiation with a 525 nm light which induced cis -> trans isomerization restored the system to the initial phase (N).The photo-induced phase transition was found to be strongly dependent on molecular weight of the host PLC and temperature.