Activation Entropy as a Key Factor Controlling the Memory Effect in Glasses

Song, Lijian; Xu, Wei; Huo, Juntao; Li, Fushan; Wang, Limin; Ediger, M. D.; Wang, Junqiang

doi:10.1103/physrevlett.125.135501

Cited by 31 publications

(22 citation statements)

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“…Recent work with metallic glasses has suggested that on short time scales, as reported here, it may be useful to separate out secondary relaxation processes into enthalpy and entropy changes. 29 Electric field measurements, similar to those reported here, may also prove useful in studying memory effects in the rejuvenation of glasses successively annealed to different temperatures on short time scales, which have been reported for a variety of glassy materials. 30,31 AC&MRVJ thank the Danish National Research Foundation (Center for Interstellar Catalysis, DNRF150 & Center for Materials Crystallography, DNRF93, respectfully) and the Danish Agency for Science, Technology, and Innovation for funding the instrument center DANSCATT.…”

Section: Figure 1 Isothermal Surface Potential Decay A-csupporting

confidence: 73%

A mechanism for ageing in a deeply supercooled molecular glass

et al. 2021

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Section: Figure 1 Isothermal Surface Potential Decay A-csupporting

confidence: 73%

A mechanism for ageing in a deeply supercooled molecular glass

et al. 2021

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“…The typical phenomenology of glassy systems includes, among other aspects, strongly nonexponential relaxation [4][5][6][7][8][9][10][11][12][13][14][15]. The latter facilitates the emergence of memory effects like the Kovacs hump [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Strong nonexponential relaxation and memory effects in a fluid with nonlinear drag

2021

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We analyze the dynamical evolution of a fluid with nonlinear drag, for which binary collisions are elastic, described at the kinetic level by the Enskog-Fokker-Planck equation. This model system, rooted in the theory of nonlinear Brownian motion, displays a really complex behavior when quenched to low temperatures. Its glassy response is controlled by a long-lived nonequilibrium state, independent of the degree of nonlinearity and also of the Brownian-Brownian collisions rate. The latter property entails that this behavior persists in the collisionless case, where the fluid is described by the nonlinear Fokker-Planck equation. The observed response, which includes nonexponential, algebraic, relaxation, and strong memory effects, presents scaling properties: the time evolution of the temperature-for both relaxation and memory effects-falls onto a master curve, regardless of the details of the experiment. To account for the observed behavior in simulations, it is necessary to develop an extended Sonine approximation for the kinetic equation-which considers not only the fourth cumulant but also the sixth one.

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“…The only possible justification is that after the energy landscape is tilted to make the ordinary SCL the equilibrium state for the thick films, a driving force is generated for the system to rapidly dilate. This phenomenon appears analogous to volume recovery of pressurized glasses (52) after the pressure is removed or memory effects in physical aging after a temperature up-jump event (53,54), both of which result in volume evolution that is faster than the nominal relaxation times of the system. Here, the change in the energy landscape from the thin-film geometry to the bulk state appears to trigger a similar effect, resulting in apparent dilation that is faster than the equilibrium relaxation times of the system.…”

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confidence: 88%

Glasses denser than the supercooled liquid

Jin

Zhang

Wolf

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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When aged below the glass transition temperature, Tg, the density of a glass cannot exceed that of the metastable supercooled liquid (SCL) state, unless crystals are nucleated. The only exception is when another polyamorphic SCL state exists, with a density higher than that of the ordinary SCL. Experimentally, such polyamorphic states and their corresponding liquid–liquid phase transitions have only been observed in network-forming systems or those with polymorphic crystalline states. In otherwise simple liquids, such phase transitions have not been observed, either in aged or vapor-deposited stable glasses, even near the Kauzmann temperature. Here, we report that the density of thin vapor-deposited films of N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) can exceed their corresponding SCL density by as much as 3.5% and can even exceed the crystal density under certain deposition conditions. We identify a previously unidentified high-density supercooled liquid (HD-SCL) phase with a liquid–liquid phase transition temperature (TLL) ∼35 K below the nominal glass transition temperature of the ordinary SCL. The HD-SCL state is observed in glasses deposited in the thickness range of 25 to 55 nm, where thin films of the ordinary SCL have exceptionally enhanced surface mobility with large mobility gradients. The enhanced mobility enables vapor-deposited thin films to overcome kinetic barriers for relaxation and access the HD-SCL state. The HD-SCL state is only thermodynamically favored in thin films and transforms rapidly to the ordinary SCL when the vapor deposition is continued to form films with thicknesses more than 60 nm.

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Activation Entropy as a Key Factor Controlling the Memory Effect in Glasses

Cited by 31 publications

References 50 publications

A mechanism for ageing in a deeply supercooled molecular glass

A mechanism for ageing in a deeply supercooled molecular glass

Strong nonexponential relaxation and memory effects in a fluid with nonlinear drag

Glasses denser than the supercooled liquid

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