Spectroscopic evidence of octahedral iron (III) in soda-lime silicate glasses
Abstract
Optical X-ray and Mössbauer absorption spectroscopies were used to observe the environment of Fe3+ ions in oxidized soda-lime silicate glasses (with 0.3, 3 and 8% Fe2O3), melted at 1450°C. The Mössbauer lineshapes show magnetic relaxation phenomena. Optical absorption spectra are mainly characterized by peaks of ferric iron in fourfold environment and, for the 0.3% Fe2O3 glass, by two bands near 1100 and 1600 cm−1 attributed to the sixfold environment. These two bands are not detected in samples with higher iron concentrations. X-ray absorption spectra of the 3 and 8% Fe2O3 glasses present in a split pre-edge in which fine structure confirms the presence of trivalent iron in the two coordinations.