Scandium fluorophosphate glasses: a structural approach

A systematic investigation on glass formation in the ternary system InF₃–BaF₂–Sc(PO₃)_3n has been carried out. Scandium polyphosphate Sc(PO₃)_3n has been used as a third component in order to investigate the possibilities of obtaining new stable glasses. The above long-chain polyphosphate has been prepared using a specially elaborated cryo-technique, which allowed the preparation of high-purity product. Stable ternary compositions have been obtained within the compositions range (in mol%): 5–75 InF₃, 0–80% BaF₂, 0–50% Sc(PO₃)_3n. Glasses were characterized by Differential Scanning Calorimetry, vibrational spectroscopy (Raman) and ³¹P NMR. Structural features for the glass were put forward. Isolated P(O,F)4 groups or fluoroindated metaphosphate units could be identified depending on glass compositions.