DIELECTRIC-RELAXATION AND LOCAL MODES OF INTRACHAIN MOBILITY IN LIQUID-CRYSTALLINE OLIGOMERS CONTAINING 4-CYANOAZOBENZENE SIDE-GROUPS

Local modes of intrachain mobility in the comb-shaped liquid-crystalli ne oligoacrylates containing side mesogenic 4-cyanoazobenzene groups a nd spacers composed of 3, 5, 7, 9, and 11 CH2 groups were studied by d ielectric spectroscopy. The existence of the two regions of dipole pol arization relaxation was revealed. These regions are associated with t he rotational mobility of mesogen (the beta-relaxation process) and me thylene spacer (the gamma(1)-relaxation process). The relaxation times of the beta-relaxation transition are independent of the length of sp acer and are almost the same for polymers with different structure. Th e kinetic parameters of the gamma(1)-process are shown to depend marke dly on the number of methylene groups in the spacer. The orientation o f mesogenic groups (homeotropic or planar) has no effect on the local modes of motion.