Decaying and steady currents in an epoxy polymer at high electric fields

Measurements are reported of the effect of field and temperature on decaying and steady currents in an epoxy polymer. Fields up to 140 MV m −1 were used and the steady current was found to increase as exp (α F ½ ). The decaying currents followed the t − n law and increased much less rapidly with increasing field and temperature than did the steady currents. Absorption of water by the polymer caused a marked increase in steady-state conduction but the current characteristics were similar to those of dried specimens. It is suggested that the decaying currents are due to electronic hopping conduction, whereas the steady currents are ionic.