Mössbauer and infra-red spectra of some alkaline earth phosphate and borate glasses

Abstract

Mössbauer and infra-red spectra were measured for a series of alkaline earth phosphate and borate glasses with mole% composition (100 - x) P 2O 5 + x MeO + 5 SnO 2 (where Me = Mg, Ca, Sr or Ba and x = 20, 24, 28 or 32). The results were analyzed as a function of glass composition and tin atoms valence state. The decrease in the isomer shift (IS) value with the increase of the alkaline earth oxide content was attributed to an increase in the ionic strength of bonds around the tin ions. The increase of the quadrupole splitting (QS) and the line width (LW) values with the gradual increase of alkaline earth oxide content were attributed to be due to an asymmetric and irregular distribution of alkaline earth ions around the tin ions. There is non-significant variation between these parameters when results for phosphate and borate glasses are compared. The asymmetry in the absorption peak is due to Goldanskii effect. The tin was found only in the quadrivalent state. The effect of tin on the infra-red absorption peaks was also studied and the different phosphorous groups were determined.