Abstract
Thermally stimulated depolarisation current (TSDC) and time-dependent conduction current of unirradiated and gamma-irradiated pure and CoCl2-doped PVA films have been measured. Doses in the range 21-75 Mrad were used. The TSDC of pure and doped PVA before and after irradiation revealed a T(g) relaxation peak. The induced changes in the peak current (I(m)) of the glass relaxation peak are composition and dose dependent. A marked decrease in TSDC corresponding to the main glass relaxation peak is observed with ageing time. The role of gamma-irradiation in perturbing the orientation of the dipoles and/or chain segments was inferred from the disappearance of some sub-T(g) relaxation peaks. The thermally activated mobility of charge carriers is confirmed from calculations of drift mobility at different gamma doses and temperatures.