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

Abstract Glasses with the compositions x Na 2 O · 10MgO · (90 − x )SiO 2 , 10Na 2 O · x MgO · (90 − x )SiO 2 , 5Na 2 O · 15MgO · x Al 2 O 3 · (80 − x )SiO 2 , x Na 2 O · 10MgO · 10Al 2 O 3 · (80 − x )SiO 2 , 10Na 2 O · 10MgO · x Al 2 O 3 · (80 − x )SiO 2 , 10Na 2 O · 5MgO · 10Al 2 O 3 · (80 − x )SiO 2 were melted and studied using UV–vis–NIR spectroscopy in the wavenumber range from 5000 to 30 000 cm −1 . At [Al 2 O 3 ] > [Na 2 O], the UV-cut off is strongly shifted to smaller wavenumbers and the NIR peak at around 10 000 cm −1 attributed to Fe 2+ 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.