Effects of gamma irradiation on photoluminescence and activation energy of epoxy resin

In this paper, photoluminescence (PL) measurements as a function of temperature (T) are-carried out to study the effect of gamma irradiation on an epoxy-based polymer. A series of epoxy resin samples are irradiated by gamma-rays with doses varying from of 10-40 kGy. The PL spectra of both non-irradiated and irradiated epoxy resin are formed by a wide asymmetric band attributed to the PL of the chromophores chain. The PL intensity is found to decrease as the temperature increases. This behavior is attributed to the dynamic transfer of the photo-induced carriers in the resin with absorbed doses, via phononic interaction, and indicates a marked dependence of the absorbed doses showing the optical activation of the traps center. Finally, the PL integrated intensity as a function of 1/T is simulated by the Arrhenius model with two activation energies for non-irradiated and irradiated sample at 10 kGy, while for doses superior to 10 kGy, a simple model of one activation energy is used. These models show that the gamma irradiation decreases the activation energy. (C) 2012 Elsevier Ltd. All rights reserved.