Disentangling density and temperature effects in the viscous slowing down of glassforming liquids

Abstract

We present a consistent picture of the respective role of density and temperature in the viscous slowing down of glassforming liquids and polymers. Specifically, based in part upon a new analysis of simulation and experimental data on liquid ortho-terphenyl, we conclude that a zeroth-order description of the approach to the glass transition should be formulated in terms of a temperature-driven super-Arrhenius activated behavior rather than a density-driven congestion or jamming phenomenon. The density plays a role at a quantitative level, but its effect on the viscosity and the structural relaxation time can be simply described via a single parameter, an effective interaction energy that is characteristic of the high temperature liquid regime; as a result, density does not affect the ``fragility'' of the glassforming system.

arXiv commentRevTeX4, 8 pages, 8 eps figures

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• Thermodynamics of glasses: a first principle computation
• Neutron Scattering Studies of the Model Glass Former Ortho-terphenyl
• Dynamics and Configurational Entropy in the LW Model for Supercooled Orthoterphenyl

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