AGING EFFECTS IN POLY(DTH SUCCINATE) OBSERVED WITH THERMAL-STIMULATEDPOLARIZATION AND DEPOLARIZATION EXPERIMENTS

Thermal-stimulated polarization and depolarization experiments with bl ocking electrodes are performed on a particular tyrosine-derived polya rylate: poly(DTH succinate). Aging effects on this sample are observed for the glass transition relaxation peak and the charge redistributio n peak originated by the conduction though the sample when blocking el ectrodes are present. The high temperature region where these peaks ar e present is modeled, and results are presented as a function of aging time. The model describes the experimental data to better than 1% for all the aging times. Contributions between the two peaks modeled are found to be constant and independent of aging. The glass transition te mperature is constant within a fraction of a degree, and the shift of the maximum temperature of the spectrum is due to the charge redistrib ution peak. The results obtained suggest that the variation in shape o f these peaks is originated by the change in the mobility of the polym eric chains, affecting in different manners the dipole orientation mec hanism, as well as conduction through the sample. A simple logarithmic aging time dependence is found for most of the parameters used in the model. (C) 1998 John Wiley & Sons, Inc.