Hecksher Tina, Olsen Niels Boye, Dyre Jeppe C
Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark
Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark.
Proc Natl Acad Sci U S A. 2019 Aug 20;116(34):16736-16741. doi: 10.1073/pnas.1904809116. Epub 2019 Aug 7.
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.
本文给出了硅油四甲基-四苯基三硅氧烷的物理老化数据。从完全平衡的条件开始，在温度跃升后监测密度和高频平台剪切模量[公式：见正文]。这两个量在温度跃升后立即呈现快速变化。采用纳拉亚纳斯瓦米的材料-时间形式理论，我们从0.178赫兹的介电损耗确定老化速率活化能的时间演化。活化能快速变化的相对幅度与密度的不同，但与[公式：见正文]的相同。实际上，在整个老化过程中，活化能与[公式：见正文]成正比，在最短时间时有微小偏差。这表明对于所讨论的硅油，其动力学在平衡态和非平衡态下均由[公式：见正文]决定。
