Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session Z16: Molecular and Polymeric Glasses
11:30 AM–2:30 PM,
Friday, March 18, 2022
Room: McCormick Place W-184A
Sponsoring Units: DPOLY DSOFT DCP DMP
Chair: Peter Olmsted, Georgetown University
Abstract: Z16.00010 : Single-parameter aging in molecular glasses*
1:18 PM–1:54 PM
In a series of papers we have shown how physical aging can be described by a single-parameter scenario through precise measurements and careful temperature protocols. Single-parameter aging is a reformulation of the Tool-Narayanaswamy idea of a fictive temperature controlling the state of the system - as well as the property monitored - during aging.
In addition, our measurements show that: 1) the high-frequency shear elastic modulus governs the relaxation rate during aging for DC704 (tetra-phenyl tetra-methyl trisiloxane), thus suggesting that in equilibrium the temperature dependence of could explain the non-Arrhenius behavior of the relaxation time (the shoving model); 2) a terminal relaxation rate exists in nonlinear relaxation curves of squalane, which is difficult to resolve in linear spectroscopic measurements; 3) non-linear aging can be predicted from equilibrium fluctuations in the molecular liquids VEC (4-vinyl-1,3-dioxolan-2-one) and NMEC (N-methyl-ε-caprolactam), as well as in computer simulations of a binary Lennard-Jones liquid.
These findings may be general for supercooled liquids.
*This work is supported by VILLUM Foundation's Matter Grant (No. 16515)
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