SYNTHESIS, THERMAL AND PHASE-CONJUGATE PROPERTIES OF SEMIRIGID COPOLYESTERS WITH CYANOAZOBENZENE SIDE-CHAINS AND AZOXYBENZENE UNITS IN THE MAIN CHAINS

Melt polycondensation of a mixture of diethyl 4-(4-cyanophenylazo)phen oxy]-hexyloxy)isophthalate and 4,4'-bis(ethoxycarbonyl)azoxybenzene at various mole ratios with dihydroxyhexamethyleneoxy derivatives of dip henyls in the presence of zinc acetate afforded new combined-type semi -rigid copolyesters containing cyanoazobenzene side chains and an azox ybenzene unit in the main chain, which were characterized by FTIR, H-1 and C-13 NMR spectroscopy and elemental analyses. Differential scanni ng calorimetry (DSC) measurements and observations in the polarizing m icroscope demonstrated that some cyanoazobenzene-rich copolyesters com posed of diphenyl ether and benzophenone units form liquid crystalline (LC) phases, but the others have no LC phases in spite of introductio n of an azoxybenzene mesogen into the polymer backbone. Most of the co polymers consisting of diphenyl ether and benzophenone units generated simultaneously two types of phase-conjugate (PC) signals based on pho to-induced anisotropy (PA) and holographic components at high reflecti vities 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 conjug ator, but also as erasable hologram-recording materials. It is suggest ed that the presence of the cyanoazobenzene side chains is of importan ce for the PC signal-generating process.