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

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This paper presents physical-aging data for the silicone oil tetramethyl-tetraphenyl trisiloxane. The density and the highfrequency plateau shear modulus G1 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 G1. In fact, the activation energy is proportional to G1 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 G1 in—as well as out of—equilibrium.
TidsskriftProceedings of the National Academy of Sciences of the United States of America
Udgave nummer34
Sider (fra-til)16736-16741
Antal sider6
StatusUdgivet - 20 aug. 2019

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