Study of the relaxation process in a side-chain copolymer functionalized with the nonlinear optical chromophore DR13

摘要

A side-chain copolymer of methylmethacrylate and a methacrylate functionalized with the nonlinear optical, NLO, chromophore 4-[N-ethyl-N-(2hydroxyethyl)]-2'-[chloro-4-nitroazobenzene], DR13, was investigated. The isothermal decay of the electro-optic coefficient, r/sub 13/, was fitted with the Kohlraush-Williams-Watts, KWW, stretched exponential allowing temperature, T/sub G/, to be determined. Above T/sub G/, /spl tau/ was obtained from dielectric loss measurements also using the KWW equation. It was concluded that such relaxation, associated with the chromophore, follows the a relaxation of the copolymer. Its dependence on temperature has the Arrhenius behavior below T/sub G/ and the Vogel-Fulcher-Tammann (VFT) behavior above T/sub G/. An attempt was also made to investigate the applicability of the Dissado-Hill model to account for the r/sub 13/ decay.