Photoluminescence, recombination induced luminescence and electroluminescence in epoxy resin

The dielectric breakdown of epoxies is preceded by light emission, or so-ca lled electroluminescence, from the solid state material. Very little is kno wn about the luminescence properties of epoxies. The aim of this paper is t o derive information that can be used as a basis with which to understand t he nature of the excited states and their involvement in the electrical deg radation processes. Three different kinds of stimulation were used to excit e the material luminescence. Photoluminescence was performed on the base re sin, the hardener and the cured resin. Luminescence excited by a silent dis charge has been analysed to identify which of the luminescent centres are o ptically active upon the recombination of electrical charges and could ther efore act as charge traps. Finally, the electroluminescence spectrum has be en acquired and compared with the previous ones. Although the identificatio n of the origin of these emissions is far from being complete, it has been found that the photoluminescence from the cured resin is due to in-chain ch romophores, which act as trapping centres. The excited states involved in p hotoluminescence also seem to be involved in electroluminescence, but other components are detected as well, which could be due to the degradation of the resin molecule under the effect of the electric stress.