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Chemical Basis of the Structural Modification in Sodium Borovanadate Glasses. Thermal and Spectroscopic Studies

Muthupari, S and Prabakar, S and Rao, KJ (1994) Chemical Basis of the Structural Modification in Sodium Borovanadate Glasses. Thermal and Spectroscopic Studies. In: Journal of Physical Chemistry, 98 (10). pp. 2646-2652.

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Abstract

Sodium borovanadate glasses have been investigated using infrared spectroscopy (IR) and magic angle spinning nuclear magnetic resonance (MAS NMR) studies. It is found that modification of borovanadate glass structure leads to the formation of tetrahedral boron and the ratio of tetrahedral $(B_4)$ to trigonal boron $(B_3)$ exhibits a maximum value of unity in these systems. A structural model has been proposed for these glasses keeping in view this observation. The model, which envisages formation of two isomorphous diborovanadate species whose structures are similar to that of diborate units, is able to account for the variation of $B_4/B_3$ ratio over the entire composition range. Variation of the glass transition temperature of these glasses has been investigated using the structural model in conjunction with cluster-tissue model of glass transition. It is emphasized throughout that electronegativities of structural units are of vital importance in understanding local oxide ion reactions which results in structural modification.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to American Chemical Society.
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 19 Oct 2006
Last Modified: 19 Sep 2010 04:31
URI: http://eprints.iisc.ernet.in/id/eprint/8318

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