ON THE NATURE OF THERMALLY STIMULATED DISCHARGE CURRENT SPECTRA IN POLYETHYLENE TEREPHTHALATE

Thermally stimulated depolarization currents (TSDC) in polyethylene te rephthalate (Hostaphan) films of different thickness (12, 25, and 50 m u m) have been investigated under different environmental conditions i n the temperature range of 20-150 degrees C. Two peaks of TSDC spectra observed at approximately 80 and 125 degrees C originate from a dipol ar process (alpha peak) and a space-charge relaxation (ppeak), as evid enced from the variation of parameters such as electrode geometry and polarizing voltage. A numerical method (Tikhonov regularization proced ure) has been employed to determine the most probable values of effect ive frequency factors of dipolar and space-charge relaxation in polyet hylene terephthalate. An apparent influence of environmental pressure on the location of the alpha peak has been observed whose origin is ye t to be determined. (C) 1998 American Institute ofPhysics.