Transient and thermally stimulated depolarization currents in polyvinyl formal films

Transient currents in double-sided vacuum aluminized polyvinyl formal (PVF) film samples of thickness 40 μm were investigated in the charge and discharge modes at different temperatures and fileds. The results observed suggest that the transient currents are governed by charge injection processes leading to space charge effects. Comparative studies of the isochronal characteristics (i.e. current–temperature plots at fixed times) with the thermally stimulated discharge current (TSDC) indicated a strong resemblance between the two techniques. These studies suggest that the simultaneous mechanism of movement of charges through microscopic distances coupled with dipolar orientation may be responsible for the TSDC peak observed at 100°C.