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Updated: May 11, 2025

Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures
Published on: June 28, 2017
Prigogine-Defay ratio of glassy freezing scales with liquid fragility
A Loidl1, P Lunkenheimer1, K Samwer2
1University of Augsburg, Experimental Physics V, 86135 Augsburg, Germany.
Abstract:
A detailed study of published experimental data for a variety of materials on the incremental variation of heat capacity, thermal expansion, and compressibility at glassy freezing reveals a striking dependence of the Prigogine-Defay ratio R on the fragility index m. At high m, R approaches values of ∼1, the Ehrenfest expectation for second-order continuous phase transitions, while R reaches values >20 for low fragilities. We explain this correlation by the degree of separation of the glassy freezing temperature from a hidden phase transition into an ideal low-temperature glass.
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