Molecular dynamics of liquid-crystalline side-group polymers with fluorine-containing azobenzene chromophores

Dielectric measurements on liquid-crystalline polymethacrylates with 4'-trifluoromethoxy-azobenzene mesogenic side groups and aikylene spacers of varying length (2-6) are reported. Several relaxation regions have been identified. The beta-process (rotational fluctuation of the mesogenic unit around its long asis) and the delta-relaxation (rotational fluctuations of the mesogen around the shea axis) show a behavior which is similar to that of the corresponding systems with phenylbenzoate as the mesogenic unit. The relaxation behavior of the intermediate alpha-process is quite unusually and has not been understood fully at present.