Infrared and MAS NMR studies of potassium borovanadate glasses

Glass system of the composition xK(2)O-(90 - x)B2O3-10V(2)O(5) (where x = 10, 20, 30, 40, and 50 mol%) have been prepared by melt quenching technique and characterized for their densities, and glass transition temperatures. The structure of the glasses has been investigated using infrared and magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The structural changes occur due to the addition of modifier oxide. Modification is based on the Sanderson's elect ronegativity principle, leading to the formation of [B2V2O9](2-) (type I and type II), [BO4/2](-) and [BO2/2O](-). This is followed by a structural rearrangement that is the ratio of B-4/B-4 + B-3 = N-4 increases up to 40 K2O mol%, further increase in modifier oxide concentration levels off N-4. The nature of speciation is examined using structural model. The variation of different properties is consistent with this model. (C) 2008 Elsevier B.V. All rights reserved.