Dielectric Dispersion in Solid Polyvinyl Butyral

Dielectric dispersion in solid polyvinyl butyral was investigated at frequencies of 0.3, 1, 3, 10, 30, and 100 kc. at temperatures from 20° to 140 °C. The data indicated severely restricted dipole rotation and yielded an extrapolated relaxation time of 10 4 sec. at 25 °C. The application of the theory of absolute reaction rates yielded an enthalpy of dielectric relaxation of 65.2 kcal. and a constant entropy of 139 e.u. These values furnish a basis for a quantitative measure of dipole hindrance and were compared with data available for other polymers.