An equilibrium supercooled liquid’s entropy and enthalpy in the Kauzmann and the third law extrapolations, and a proposed experimental resolution
An equilibrium supercooled liquid’s entropy and enthalpy in the Kauzmann and the third law extrapolations, and a proposed experimental resolution
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DOI：
10.1063/1.481850
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发表时间：
2000-06
影响因子：
4.4
通讯作者：
G. P. Johari
中科院分区：
文献类型：
--
作者：
G. P. Johari
In our current discussion of the thermodynamics and molecular kinetics of glass-forming liquids, the entropy is extrapolated below a liquid’s vitrification temperature Tg along a curve of progressively increasing slope until a temperature Tk is reached. Here the entropy and heat capacity, Cp, of the equilibrium liquid become equal to those of its crystal. Several observations have indicated fundamental difficulties with this extrapolation, thus suggesting the need for an alternative. We propose one alternative, in which Cp of an equilibrium liquid decreases along a sigmoid-shape path stretched over a broad temperature range from above Tg to 0 K. Its entropy and Cp become equal to those of its crystal at 0 K, as required by the third law of thermodynamics, and the enthalpy and volume remain higher. To elaborate, the available Cp data of 12 supercooled liquids have been interpolated between T>Tg and 0 K, and the enthalpy of their equilibrium state at 0 K, as well as the Gibbs free energy and enthalpy at T
