Thermally-Stimulated Polarization Current of Poly (Ethylene Terephthalate) Upon Heating, Cooling, and Reheating

Abstract

Thermally-stimulated polarization current was measured for poly (ethylene terephthalate) film. When the freshly-annealed film was heated under the application of a high field, the current was positive at the beginning and turned negative at an intermediate temperature and then returned positive. In the successive cooling, a positive current was observed. Then the test piece was heated again and a negative current was observed until high temperature where ohmic current prevailed. These phenomena can be explained by considering the displacement current due to polarization: the saturation values in polarization for every relaxation mode are inversely proportional to temperature and hence polarizations increase by cooling and decrease by heating. © 1981, The Society of Polymer Science, Japan. All rights reserved.