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Synthesis, thermal and phase‐conjugate properties of semirigid copolyesters with cyanoazobenzene side‐chains and azoxybenzene units in the main chains
Author(s) -
Sato Moriyuki,
Nakagawa Kazuo,
Hayakawa Makoto,
Mukaida Kenichi,
Fujiwara Hirofumi,
Tada Yuji
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021960919
Subject(s) - side chain , differential scanning calorimetry , polymer chemistry , mesogen , materials science , polymer , phase (matter) , copolymer , benzophenone , fourier transform infrared spectroscopy , condensation polymer , chemistry , organic chemistry , chemical engineering , liquid crystalline , physics , engineering , composite material , thermodynamics
Melt polycondensation of a mixture of diethyl 5‐{6‐[4‐(4‐cyanophenylazo)phenoxy]‐hexyloxy}isophthalate and 4,4′‐bis(ethoxycarbonyl)azoxybenzene at various mole ratios with dihydroxyhexamethyleneoxy derivatives of diphenyls in the presence of zinc acetate afforded new combined‐type semi‐rigid copolyesters containing cyanoazobenzene side chains and an azoxybenzene unit in the main chain, which were characterized by FTIR, 1 H and 13 C NMR spectroscopy and elemental analyses. Differential scanning calorimetry (DSC) measurements and observations in the polarizing microscope demonstrated that some cyanoazobenzene‐rich copolyesters composed of diphenyl ether and benzophenone units form liquid crystalline (LC) phases, but the others have no LC phases in spite of introduction of an azoxybenzene mesogen into the polymer backbone. Most of the copolymers consisting of diphenyl ether and benzophenone units generated simultaneously two types of phase‐conjugate (PC) signals based on photo‐induced anisotropy (PA) and holographic components at high reflectivities by degenerate four‐wave mixing (DFWM) at low pump‐beam powers, which are one of the third‐order non‐linear optical (NLO) properties. This means that these copolyesters can be used not only a phase conjugator, but also as erasable hologram‐recording materials. It is suggested that the presence of the cyanoazobenzene side chains is of importance for the PC signal‐generating process.