Specific heat relaxation-based critique of isothermal glass transition, zero residual entropy and time-average formalism for ergodicity loss

Johari, G. P.

doi:10.1016/j.tca.2011.05.005

Cited by 17 publications

(16 citation statements)

References 65 publications

(233 reference statements)

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“…By these and all other reasons briefly summarized above, we do not consider it as possible to find some compromise reconciling the traditional and the newly advanced entropy-loss concepts as proposed in [ 137 ]. Instead, we fully support the conclusion derived by Johari [ 106 ], already cited above, but worth being repeated as a general resume: “ The premise that glass formation is a process of continuously breaking ergodicity with entropy loss does not merit serious consideration ”.…”

Section: Summary Of Results and Discussionsupporting

confidence: 87%

“…We find that an increase in the real component of elastic moduli with an increase in spectral frequency does not indicate continuous loss of ergodicity and entropy, and the spectra do not confirm isothermal glass transition or loss of entropy ”. In [ 106 ], he added, “ In support of the view that entropy is lost on glass formation, the

relaxation spectra were regarded as experimental proof of time- and temperature-dependent loss of both ergodicity and entropy, and confirmation of isothermal glass transition. Also, both

and

in the limits of

s, and

K were cited as further proof … The notions of partial ergodicity and entropy and their dependence on

are inconsistent with the properties measured during cooling, heating and isothermal annealing, and thermodynamic consequences of the apparent proof are untenable.…”

Section: Residual Entropy Of Glassesmentioning

confidence: 99%

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Glass Transition, Crystallization of Glass-Forming Melts, and Entropy

Schmelzer¹,

Тропин

2018

Entropy

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A critical analysis of possible (including some newly proposed) definitions of the vitreous state and the glass transition is performed and an overview of kinetic criteria of vitrification is presented. On the basis of these results, recent controversial discussions on the possible values of the residual entropy of glasses are reviewed. Our conclusion is that the treatment of vitrification as a process of continuously breaking ergodicity with entropy loss and a residual entropy tending to zero in the limit of zero absolute temperature is in disagreement with the absolute majority of experimental and theoretical investigations of this process and the nature of the vitreous state. This conclusion is illustrated by model computations. In addition to the main conclusion derived from these computations, they are employed as a test for several suggestions concerning the behavior of thermodynamic coefficients in the glass transition range. Further, a brief review is given on possible ways of resolving the Kauzmann paradox and its implications with respect to the validity of the third law of thermodynamics. It is shown that neither in its primary formulations nor in its consequences does the Kauzmann paradox result in contradictions with any basic laws of nature. Such contradictions are excluded by either crystallization (not associated with a pseudospinodal as suggested by Kauzmann) or a conventional (and not an ideal) glass transition. Some further so far widely unexplored directions of research on the interplay between crystallization and glass transition are anticipated, in which entropy may play-beyond the topics widely discussed and reviewed here-a major role.

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Section: Summary Of Results and Discussionsupporting

confidence: 87%

relaxation spectra were regarded as experimental proof of time- and temperature-dependent loss of both ergodicity and entropy, and confirmation of isothermal glass transition. Also, both

and

in the limits of

s, and

K were cited as further proof … The notions of partial ergodicity and entropy and their dependence on

are inconsistent with the properties measured during cooling, heating and isothermal annealing, and thermodynamic consequences of the apparent proof are untenable.…”

Section: Residual Entropy Of Glassesmentioning

confidence: 99%

Glass Transition, Crystallization of Glass-Forming Melts, and Entropy

Schmelzer¹,

Тропин

2018

Entropy

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“…[5][6][7][8] However, it has to be pointed out that these two aspects of glassy dynamics are in principle different from a conceptual viewpoint. 9,10 In particular, while the rate of spontaneous fluctuations represents an intrinsic property of the unperturbed system, measuring the T g or the kinetics of equilibrium recovery implies the application of perturbations larger than the amplitude of spontaneous fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Complex nonequilibrium dynamics of stacked polystyrene films deep in the glassy state

Boucher¹,

Cangialosi²,

Alegría

et al. 2017

The Journal of Chemical Physics

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We investigate the kinetics of enthalpy recovery in stacked glassy polystyrene (PS) films with thickness from 30 to 95 nm over a wide temperature range below the glass transition temperature (T). We show that the time evolution toward equilibrium exhibits two mechanisms of recovery, in ways analogous to bulk PS. The fast mechanism, allowing partial enthalpy recovery toward equilibrium, displays Arrhenius temperature dependence with low activation energy, whereas the slow mechanism follows pronounced super-Arrhenius temperature dependence. In comparison to bulk PS, the time scales of the two mechanisms of recovery are considerably shorter and decreasing with the film thickness. Scaling of the equilibration times at various thicknesses indicates that the fast mechanism of recovery is compatible with the free volume holes diffusion model. Conversely, the slow mechanism of recovery appears to be accelerated with decreasing thickness more than predicted by the model and, therefore, its description requires additional ingredients. The implications, from both a fundamental and technological viewpoint, of the ability of thin polymer films to densify in relatively short time scales are discussed.

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“…Given this premise, it is worth remarking that conceptually, vitrification and molecular mobility are different aspects of glassy dynamics [1,6]. The former entails information on how equilibrium is lost upon cooling the equilibrated melt or recovered in the glassy state.…”

mentioning

confidence: 99%

Thermodynamic Ultrastability of a Polymer Glass Confined at the Micrometer Length Scale

Monnier

Cangialosi

2018

Phys. Rev. Lett.

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We employ fast scanning calorimetry to assess the thermodynamic state attained after a given cooling rate and the molecular mobility of glassy poly(4-tert-butylstyrene) confined at the micrometer length scale. We show that, for such a large confinement length scale, thermodynamic states with a fictive temperature (T f) 80 K below the polymer glass transition temperature (T g) are attained, which allows to bypass the geological timescales required for bulk glasses. Access to such states is promoted by a fast mechanism of equilibration. Importantly, the tremendous T f decrease takes place while the molecular mobility remains bulklike, indicating marked decoupling between vitrification kinetics and molecular mobility.

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Specific heat relaxation-based critique of isothermal glass transition, zero residual entropy and time-average formalism for ergodicity loss

Cited by 17 publications

References 65 publications

Glass Transition, Crystallization of Glass-Forming Melts, and Entropy

Glass Transition, Crystallization of Glass-Forming Melts, and Entropy

Complex nonequilibrium dynamics of stacked polystyrene films deep in the glassy state

Thermodynamic Ultrastability of a Polymer Glass Confined at the Micrometer Length Scale

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