The observation of photo-stimulated discharge of typical polymers by OPO laser

Photo-stimulated discharge (PSD) spectroscopy of polyester (PET), polypropylene (PP), polyimide (PI) of DuPont charged by either corona discharge or contact electrode were performed with self-made PSD measurement system in order to investigate the space charge traps of the polymers. The samples were irradiated with new type of continuously tunable wavelength laser based on the optical parametric oscillator (OPO) through the semi-transparent electrode. Experimental results indicate that the energy distribution of traps varies with different materials: there exists only one single trap energy level to be activated by OPO laser in PET, however, broad peaks spectrum in PI and PP. In the meanwhile some of deep trap are ascribed to factors like additives such as cross-linking agent. The effect of molecular motions on thermal erosion of the traps was also investigated.