Local forms of molecular mobility in copolymethacrylates containing side-chain nonlinear optical chromophores

Local forms of molecular mobility of comb-like random copolymethacrylates, containing side-chain nonlinear optical chromophores and amyl- or octafluoroamyl-groups, are studied. In the glassy state, two relaxation processes are found, which are due to reorientation of terminal polar groups (gamma(2)-process) and rotation of chromophore groups about their long axes (beta-process). For octafluoroamyl-containing copolymers, the gamma(2)-process is superposition of the two molecular motions due to reorientation of terminal chromophore groups and -CF2H groups. The intensity and relaxation times in the range of the gamma(2)-process depend on the chemical structure and concentration of chromophores in a copolymer. For the beta-process, the molecular mobility weakly depends on the chromophore structure, being mainly determined by the relative lengths of the rigid chromophore and flexible side chains. On the global spectrum of depolarization current it was observed the gamma(1)-process due to reorientation of (CH2)(n) spacers between chromophore groups and copolymer backbone. (C) 2008 Wiley Periodicals, Inc.