Effect of gamma radiation on ultraviolet, visible and infrared studies of NiO, Cr2O3 and Fe2O3-doped alkali borate glasses

Borate glasses with basic composition xR(2)O.(100 - x)B2O3 where R = Na, K, were colored by doping with one of transition metal ions Ni, Cr, Fe or doping with mixing of them. The effect of glass composition and gamma ray irradiation on the optical and infrared absorption spectra was studied and interpreted in terms of structural concepts. A resolution of the observed absorption spectra showed the existence of each transition metal ion in the possible coordination state according to the composition of the glass. The IR measurements reveal characteristic absorption bands due to various groups of triangular and tetrahedral borate network. The introduction of trace amounts of mixed dopants Cr2O3, Fe2O3 and NiO has no major effect on the structure of the studied glasses. The induced absorption spectra exhibit the characteristic absorption bands caused by the intrinsic base borate glass and the respective transition metal ions. The response of the doped glasses to gamma ray irradiation is assumed to be related to the formation and annihilation of the induced color centers. (C) 2013 Elsevier B.V. All rights reserved.