Gamma-ray interactions with WO3-doped sodium phosphate glasses

Tungsten-doped sodium phosphate glasses of various compositions and with varying WO3 contents were prepared. UV–visible and infrared spectroscopic studies were measured before and after successive gamma irradiation. Raman and ESR studies were conducted for some selected glass samples. Experimental results indicate that tungsten ions occupy two possible valences W6+ and W5+ with different local sites depending on the host glass composition and concentration of tungsten ions. The changes in UV, visible, infrared and Raman spectral data are discussed in relation to the structural evolution caused by the change in glass composition and state of tungsten ions. Electron spin resonance studies confirm the presence of unpaired W5+ ions. Tungsten ions have been found to show a shielding behavior towards the effects of progressive gamma irradiation causing a retardation of the growth of the induced defects caused by irradiation.