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Fast contribution to the activation energy of a glass-forming liquid.

ABSTRACT: This paper presents physical-aging data for the silicone oil tetramethyl-tetraphenyl trisiloxane. The density and the high-frequency plateau shear modulus [Formula: see text] were monitored following temperature jumps starting from fully equilibrated conditions. Both quantities exhibit a fast change immediately after a temperature jump. Adopting the material-time formalism of Narayanaswamy, we determine from the dielectric loss at 0.178 Hz the time evolution of the aging-rate activation energy. The relative magnitude of the fast change of the activation energy differs from that of the density, but is identical to that of [Formula: see text] In fact, the activation energy is proportional to [Formula: see text] throughout the aging process, with minor deviations at the shortest times. This shows that for the silicone oil in question the dynamics are determined by [Formula: see text] in-as well as out of-equilibrium.

SUBMITTER: Hecksher T

PROVIDER: S-EPMC6708330 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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Fast contribution to the activation energy of a glass-forming liquid.

Hecksher Tina T Olsen Niels Boye NB Dyre Jeppe C JC

Proceedings of the National Academy of Sciences of the United States of America 20190807 34

This paper presents physical-aging data for the silicone oil tetramethyl-tetraphenyl trisiloxane. The density and the high-frequency plateau shear modulus [Formula: see text] were monitored following temperature jumps starting from fully equilibrated conditions. Both quantities exhibit a fast change immediately after a temperature jump. Adopting the material-time formalism of Narayanaswamy, we determine from the dielectric loss at 0.178 Hz the time evolution of the aging-rate activation energy. ...[more]

PMID: 31391307

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