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Nonmonotonic temperature dependence of heat capacity through the glass transition within a kinetic model

Chakrabarti, Dwaipayan and Bagchi, Biman (2004) Nonmonotonic temperature dependence of heat capacity through the glass transition within a kinetic model. In: Journal of Chemical Physics, 120 (24). pp. 11678-11685.

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Abstract

The heat capacity of a supercooled liquid subjected to a temperature cycle through its glass transition is studied within a kinetic model. In this model, the beta process is assumed to be thermally activated and described by a two-level system. The alpha process is described as a beta relaxation mediated cooperative transition in a double well. The overshoot of the heat capacity during the heating scan is well reproduced and is shown to be directly related to delayed energy relaxation in the double well. In addition, the calculated scan rate dependencies of the glass transition temperature Tg and the limiting fictive temperature T L/f show qualitative agreement with the known results. Heterogeneity is found to significantly reduce the overshoot of heat capacity. Furthermore, the frequency dependent heat capacity has been calculated within the present framework and found to be rather similar to the experimentally observed behavior of supercooled liquids.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to American Physical Society (APS).
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 28 Oct 2004
Last Modified: 19 Sep 2010 04:17
URI: http://eprints.iisc.ernet.in/id/eprint/2210

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