Configurational Prigogine-Defay ratio - Physics > Chemical PhysicsReport as inadecuate

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Abstract: Classically, the Prigogine-Defay PD ratio involves differences in isobaricvolumic specific heat, isothermal compressibility and isobaric thermalexpansion coefficient between a super-cooled liquid and the corresponding glassat the glass transition. However, determining such differences by extrapolationof coefficients that have been measured for super-cooled liquid and glassystate, respectively, poses the problem that it does not take into account thenon-equilibrium character of the glass transition. In this paper, we asses thisold question by taking into account the gradual change of configurationalcontributions to the three thermodynamic coefficients upon varying temperatureand pressure. Macroscopic non-equilibrium thermodynamics is applied to obtain ageneralized form of the PD ratio. The classical PD ratio can then be taken as aparticular case of this generalization. Under some assumptions, aconfigurational PD ratio CPD ratio can be expressed in terms of fictivetemperature and fictive pressure what, hence, provides the possibility toexperimentally verify this formalism. Noteworthy and differing from previousapproaches towards the PD ratio, here, the glass transition is considered asnon-isoaffine.

Author: Jean-Luc Garden NEEL, Hervé Guillou NEEL, Jacques Richard NEEL, L. Wondraczek


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