Conduction current measurements on polycarbonates subjected to electrical and thermal stress

Results of conduction current measurements on Polycarbonate samples which underwent simultaneous electrical and thermal aging are reported. By recording the conduction current for different values of the electric field strength a transition from ohmic to high field conduction was observed. Such a characteristic change in the slope of the conduction current as function of the poling field is called a threshold. Whereas for the Polycarbonate without a filler one threshold was detected, the Polycarbonate modified by a TiO₂ filler unveiled two. Potentially important for the detection of initial aging stages, these thresholds were found to be affected by aging. In the course of an advanced aging process, the threshold decreased