Structure-Property Correlation in Sodium Borophosphate Glasses Modified with Niobium Oxide

Bulk glasses of the series (100?x)[0.4Na2O-0.2Nb2O5-0.4P2O5]-xB2O3 with x = 0–48 mol% B2O3 were prepared by slow cooling in air. Their glass transition temperature increases within range 0–16 B2O3, but further additions result its decrease. structure was investigated Raman, 11B, and 31P MAS NMR spectroscopy. The relative number BO4 units decreases increasing content, while BO3 up to 59 % at 48. upfield shift a broad resonance peak spectra is ascribed an connectedness structural network content. Strong Raman band 916–929 cm?1 shows on presence NbO6 octahedra these glasses. With addition, decrease DC conductivity observed, which attributed concentration Na+ ions.