New results concerning thermally stimulated discharge current peak above room temperature

Thermally Stimulated Discharge Current measurements an as received polarized and electron-beam charged samples as well as DC conductivity and isothermal current measurements were used in the attempt of understanding the nature of peaks above room temperature in poly(ethylene terephthalate) (PET) samples. The mechanism by which the external measured current is produced is analyzed and a new model is proposed. In this model the polarization charge and the injected charge give an heterocharge type current in very accord with experimental results. The homocharge type peaks results from adsorbed ions and only when the measurements are made at pressure higher than 5*10^-2 torr. The maximum above T_g is determined by the space-charge movement by hopping mechanisms. The stored charge comportment at high temperature can be studied by the new proposed measuring methods: Thermally Stimulated Space Charge (TSSC) and isothermal final discharging current measurement. The importance of external measuring resistance is analyzed