Photoluminescence in polymeric insulating materials (low density polyethylene and polypropylene) induced by ultraviolet photons

Photoluminescence in polymeric insulating materials induced by ultraviolet photons causing degradation of the material was investigated. The structural changes in unirradiated and irradiated samples of polypropylene (PP) and low density polyethylene (LDPE) were examined by vacuum ultraviolet (VUV) absorption spectroscopy and Fourier transform infrared absorption (FT-IR) spectroscopy. The luminescence component was found to decrease around 3.6 eV-4 eV with an increase in irradiation time due to the decomposition of unsaturated ketone or benzene ring present in polymer as an impurity or antioxidant. In vacuum the luminescence component increased with an increase in irradiation time due to double bonds induced by the irradiation.