Space charge and dielectric polarization in polymers

It is difficult to demonstrate unequivocally that the steady state conduction current in insulating polymers may originate from space charges because of the apparent field dependence of the charge mobility. However, the frequency dependent dielectric relaxation behaviour may be affected by the time dependent absorption currents in these materials. The irreversible electrical ageing in polymers under continued electrical stress can be detected by dielectric spectroscopic studies at very low frequencies.