Examining the entropy theory's application to viscosity data and the inference for a thermodynamic transition in an equilibrium liquid

The belief that the configurational entropy theory had demonstrated the validity of the Kauzmann entropy extrapolation to a temperature Tk, and had led to the inference that an Ehrenfest-type transition occurs at T-2, has been examined. It is found that the theory neither supports the Kauzmann extrapolation nor suggests an abrupt decrease in C-p of an equilibrium liquid at T-k or T-2. It is found that the inference of a thermodynamic transition was a result of two approximations: (i) the C-p of a liquid remains constant with changing temperature and (ii) the configurational entropy, S-conf, at T-g is equal to the residual entropy of a glass. Both were needed to correlate the viscosity data with the S-conf formalism. Without these, the theory seems consistent with the interpolation of an equilibrium liquid's C-p along a stretched sigmoid shape curve from 0 K to its measured value [J. Chem. Phys. 113 (2000) 751]. The known temperature dependence of a liquid's transport properties can be reconciled with its configurational entropy, S-conf, change without invoking an underlying thermodynamic transition. This puts into questions the validity of models, which had assumed that a thermodynamic transformation occurs at T-k or at T-2. (C) 2001 Elsevier Science B.V. All rights reserved.