The effect of composition on UV-vis-NIR spectra of iron doped glasses in the systems Na2O/MgO/SiO2 and Na2O/MgO/Al2O3/SiO2

Glasses with the compositions xNa(2)O center dot 10MgO center dot(90 - x)SiO2, 10Na(2)O center dot xMgO center dot(90 - x)SiO2, 5Na(2)O center dot 15MgO center dot xAl(2)O(3)center dot(80 - x)SiO2, xNa(2)O center dot 10MgO center dot 10Al(2)O(3)center dot(80-x)SiO2, 10Na(2)O center dot 10MgO-xAl(2)O(3)center dot(80-x)SiO2, 10Na(2)O-5MgO center dot 10Al(2)O(3)center dot(80-x)SiO2 were melted and studied using UV-vis-NIR spectroscopy in the wavenumber range from 5000 to 30 000 cm(-1). At [Al2O3] > [Na2O], the UV-cut off is strongly shifted to smaller wavenumbers and the NIR peak at around 10000 cm(-1) attributed to Fe2+ in sixfold coordination gets narrower. Furthermore, the intensity of the NIR peak at 5500 cm(-1) increases. This is explained by the incorporation of iron in the respective glass structures. (c) 2006 Elsevier B.V. All rights reserved.