TSC study of the polar and free charge peaks of amorphous polymers

Electrets of amorphous polyethylene-terephthalate were studied, using thermal windows to polarize and thermally stimulated depolarization current (TSDC) dielectric spectroscopy as an analysis technique. It was found that the polar peak ( alpha ) and the free charge peak ( rho ) show a maximal area at polarization temperatures, T/sub p/, called the temperature of optimal polarization, T/sub po/. The T/sub po/ of alpha is approximately=70 degrees C, and for T/sub p/, >T/sub po/ the temperature at which the maximum intensity appears remains constant with T/sub p/. For this range of temperature the intensity of the maximum decreases and the polarization is linear with 1/T/sub p/. The second peak, rho , which has a T/sub po/ approximately=87 degrees C, shows the maximum intensity at temperatures that are linear with T/sub p/, T/sub p/>T/sub po/. For this range of temperatures the intensity of the maximum decreases with T/sub p/ and the polarization is not linear with 1/T/sub p/. These results are compared with those obtained from polyvinylchloride and polymethylmethacrylate. >