DIELECTRIC RELAXATIONS IN A CO-POLYMER OF VINYLIDENE FLUORIDE AND TRIFLUOROETHYLENE

Dynamic dielectric measurements were carried out for a copolymer of vinylidene fluoride (55 mol%) and trifluoroethylene (45 mol%) over the frequency range of 50 Hz-50 MHz at temperatures between minus 15 and 130 degree C. Observed relaxations associated with a crystalline phase transition at 70 degree C were found to fit the Cole-Cole arc with a distribution of relaxation times. The equilibrium dielectric constant epsilon (0) exhibits a dielectric anomaly in that it rapidly increases to 70 just below 70 degree C and then decreases. The longarithm of the observed relaxation time tau vs 1/T(K** minus **1) shows a shoulder near 70 degree C which is interpreted as being the result of a critical slowing down phenomenon. The derived relaxation time tau //0 in the absence of cooperative effects exhibits an Arrhenius type temperature dependence from 40 to 130 degree C with a potential barrier for dipole rotation of 13 kcal/mol.