Gamma ray interactions with V2O5-doped sodium phosphate glasses

Undoped and V2O5-doped sodium phosphate glasses of various compositions and with varying progressive V2O5 contents were prepared. UV-vis and infrared, Raman and electron spin resonance spectroscopic Studies were measured before and after Successive gamma irradiation. Experimental results indicate that vanadium ions exist in three possible valencies in sodium phosphate glasses, namely, the trivalent, tetravalent and pentavalent states. The first two lower valencies are predominant in this glass system. The changes in UV-vis and infrared spectral data are discussed in relation to the structural evolution caused by the change in the V2O5 content or glass composition. Raman and ESR measurements are taken as confirmative tools to support our assumptions relating to the states of vanadium and structural groups arrangements in the studied glasses. Gamma irradiation produces induced defects depending on the host glass and the concentration of V2O5 content together with the sharing of unavoidable trace iron impurities. Vanadium ions when present in high doping level, have been found to exhibit a shielding behaviour towards the effects of progressive gamma irradiation causing a retardation of the growth of the induced defects Caused by irradiation. (C) 2008 Elsevier B.V. All rights reserved.