Absence of Germanate Anomaly in Ternary Lithium Germanophosphate lasses: Modification Behavior of Mixed Glass System of Strong and Fragile Formers

Kumar, Sundeep and Murugavel, S and Rao, KJ (2001) Absence of Germanate Anomaly in Ternary Lithium Germanophosphate lasses: Modification Behavior of Mixed Glass System of Strong and Fragile Formers. In: The Journal of Physical Chemistry B, 105 (25). pp. 5862-5873.

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Abstract

Ternary lithium germanophosphate glasses have been synthesized over a wide range of compositions. Thermal and spectroscopic techniques (IR, Raman, and $^{31}P$ MAS NMR) have been used to investigate their properties and structures. It is found that modification occurs almost exclusively on the $P_2O_5$part of the structure and the $GeO_2$ network appears unaffected. $GeO_{6/2}$octahedra are not formed in the glasses, except in one $GeO_2$-rich and $Li_2O$-poor composition. Thermodynamic arguments are given to rationalize this behavior. The unique behavior of the $T_g$values and molar volumes have been discussed in terms of a model, which considers modification occurring only on the $P_2O_5$ part of the glass structure.$F_{1/2}$fragilities of these glasses have been evaluated from \Delta $T_g$and $T_g$values, and a relation between $F_{1/2}$ and the physical dimensionality has been proposed.

Item Type:	Journal Article
Publication:	The Journal of Physical Chemistry B
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	02 Dec 2008 09:11
Last Modified:	19 Sep 2010 04:52
URI:	http://eprints.iisc.ac.in/id/eprint/16568

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