Dielectric relaxation of polyorganophosphazenes

Dielectric relaxation spectra of poly(bis-trifluoroethoxy phosphazene) (PBFP), poly(bis-n-propoxy phosphazene) (PBPP), and poly(bis-n-propylamino phosphazene) (PBPAP) were measured in wide temperature and frequency regions, and the -relaxation caused by micro-Brownian motion of segments in the rubbery state and the -relaxation due to the local motions of the polymer in the glassy region were observed. The dielectric spectra of PBFP at temperatures higher than the rubbery region exhibited a mesophase transition at 358 K. From conformation analysis according to the two-site model, it has been elucidated that the mechanism for -relaxation of these samples is hindered internal rotation of the side groups.