Origins of Chemiluminescence in Polymeric Insulating Materials

One of inevitable weak points of electrical insulation with industrially synthesized organic polymers is oxidative degradation. For detecting such oxidation induced in polymeric materials, a spectroscopic analysis method called chemiluminescence (CL) is known. It has widely been believed that singlet molecular oxygen and electronically excited triplet carbonyl products are its two luminous sources. To confirm the validity of this assumption, CL was measured for a variety of polymers. Fourier-transform mid-infrared absorption spectroscopy was also conducted before and after the CL measurements. As a result, it has become clear that the formation process of the cross-linked structure in silicone rubber by bridging two neighboring siloxane backbones via oxygen and the curing process of epoxy resin as well induce the CL.