DIELECTRIC-RELAXATION AND PHYSICAL AGING IN POLAR GLASSY-POLYMERS

The evolution of the physical aging of the dielectric response of two polar glassy polymers, poly(sulfone of bisphenol-A) and poly(vinyl acetate), was investigated. The dielectric response measured shows a clear non-exponential behavior, which can be described by a stretched exponential functional form (exp[-(t/tau-p)-beta]). Thus, the dependence on physical aging of both the characteristic timescale, tau-p, and the non-exponential parameter, beta, was studied. Moreover, the results obtained were compared with those corresponding to enthalpy recovery.