Estimates of the configurational entropy of a liquid

The entropy difference between a liquid and one of the glasses that it samp les is called the configurational entropy, S-c, and it may provide an impor tant link between dynamic and thermodynamic measures of the fragility of li quids. Most previous estimates of S-c have implicitly assumed that all glas ses of the same substance have the same entropy, but that assumption can le ad to estimates of S-c and its temperature dependence that may be wrong by a factor of 2 or more. New estimates of S-c for toluene and ethylbenzene ar e used to test relations between thermodynamic and kinetic measures of frag ility implied by Adam and Gibbs theory.