Stress and Volume Relaxation in Annealing Flat Glass

Gardon, Robert; Narayanaswamy, O. S.

doi:10.1111/j.1151-2916.1970.tb12137.x

Cited by 161 publications

(37 citation statements)

References 11 publications

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“…The idea of "fictive temperatures" [42] T f in glasses goes back to the '40s and it has developed since [43][44][45]. Here we recall it briefly, for the sake of comparison with the effective temperature that we have discussed.…”

Section: Comparison With Other Effective Temperaturesmentioning

confidence: 99%

Energy flow, partial equilibration, and effective temperatures in systems with slow dynamics

1997

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We show that, in nonequilibrium systems with small heat flows, there is a time-scale dependent effective temperature which plays the same role as the thermodynamical temperature, in that it controls the direction of heat flows and acts as a criterion for thermalization. We simultaneously treat the case of stationary systems with weak stirring and of glassy systems that age after cooling and show that they exhibit very similar behavior provided that time dependences are expressed in terms of the correlations of the system. We substantiate our claims with examples taken from solvable models with nontrivial low-temperature dynamics, but argue that they have a much wider range of validity. We suggest experimental checks of these ideas. 75.40.Gb, 75.10.Nr, Typeset using REVT E X 1

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Section: Comparison With Other Effective Temperaturesmentioning

confidence: 99%

Energy flow, partial equilibration, and effective temperatures in systems with slow dynamics

1997

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“…With an appropriate choice of the heating and cooling rates to mimic the experimental conditions, we show that both the shadow and the glass transition peaks can be resolved in the same heating scan. Finally, we compare the simulation results with the Tool-Narayanaswamy-Moynihan (TNM) phenomenological model [15,17,18].We perform NVT molecular dynamics (MD) simulations for a system of N = 216 molecules, with periodic boundary conditions. Interactions are cut off at a distance of r = 2.5σ, where σ is the length parameter defined in the SPC/E potential, and the reaction field method is implemented to account for the long range interactions.…”

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confidence: 99%

Glass-Transition Temperature of Water: A Simulation Study

et al. 2004

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We report a computer simulation study of the glass transition for water. To mimic the difference between standard and hyperquenched glass, we generate glassy configurations with different cooling rates and calculate the T dependence of the specific heat on heating. The absence of crystallization phenomena allows us, for properly annealed samples, to detect in the specific heat the simultaneous presence of a weak pre-peak ("shadow transition"), and an intense glass transition peak at higher temperature. We discuss the implications for the currently debated value of the glass transition temperature of water. We also compare our simulation results with the Tool-NarayanaswamyMoynihan phenomenological model. PACS numbers:Much recent research has focused on the properties of glassy water, the most common form of water in the universe, which can exist in more than one distinct amorphous form [1,2,3]. The conversion between different glass structures, the different routes producing glass structures, and the relation between the liquid and the glass phases are under active debate.A particularly relevant aspect of this debate concerns the identification of the glass transition temperature T g at ambient pressure and the magnitude of the associated jump of the specific heat, an issue which has relevance also for determining the fragility of water. Extrapolation of T g in binary aqueous solutions, in the limit of vanishing solute concentration, provides the estimate T g ≈ 136 K [4]. Early differential scanning calorimetry (DSC) studies report conflicting results. Some experiments detect the glass transition [5] but others do not [6]. An exothermal peak in the specific heat of properly-annealed hyperquenched water supports the estimate T g ≈ 136 K [7], with a specific heat jump of 1.6 − 1.9 J/mol/K. This T g value [8,9] has been recently debated [10,11,12]. It has been suggested[12] that the small peak measured in Ref.[7] is a pre-peak typical of annealed hyperquenched samples preceding the true glass transition located at T g ≈ 165 K. Assigning T g ≈ 165 K would explain many of the puzzles related to the glass transition in water [9,10,12]. Unfortunately, the T g ≈ 165 K proposal can not be experimentally tested due to the homogeneous nucleation of the crystal phase at T × ≈ 150 K.Here we report a numerical study of the temperature dependence of the specific heat across the glass-to-liquid transition for the extended simple point charge (SPC/E) model for water. We analyze the effects both of the cooling rate and of annealing ("aging") before heating the glass, since both effects are important for determining T g [13,14], and both effects have been studied extensively in many materials [15,16]. Numerical studies are particularly suited since crystallization does not take place on the time scale probed in simulations. With an appropriate choice of the heating and cooling rates to mimic the experimental conditions, we show that both the shadow and the glass transition peaks can be resolved in the same heating scan. Finally, we...

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“…(47)] which in the latter is not uniquely determined by the sign of AT,,, as it was in the former case [eq (19)]. In fact, depending on the sign of AT, and 6i,s and on their respective magnitudes, 6i,o can take positive or negative values and may even be equal to zero.…”

Section: Recovery During and After Complex Thermal Treatmentsmentioning

confidence: 86%

“…(18) becomes Clearly, in the present case all the 6,,0's have the same sign, opposite to that of AT [eq. (19)]. Furthermore, d6JdtT maintains its sign until 6, vanishes, since T , ,~U T U~ is strictly positive.…”

Section: Isothermal Recovery After a Single Instantaneous T-jumpmentioning

confidence: 99%

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Isobaric volume and enthalpy recovery of glasses. II. A transparent multiparameter theory

Kovacs

Aklonis

Hutchinson

et al. 1996

J. Polym. Sci. B Polym. Phys.

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SynopsisA multiordering parameter model for glass-transition phenomena has been developed on the basis of nonequilibrium thermodynamics. In this treatment the state of the glass is determined by the values of N ordering parameters in addition to T and P; the departure from equilibrium is partitioned among the various ordering parameters, each of which is associated with a unique retardation time.These times are assumed to depend on T, P, and on the instantaneous state of the system characterized by its overall departure from equilibrium, giving rise to the well-known nonlinear effects observed in volume and enthalpy recovery. The contribution of each ordering parameter to the departure and the associated retardation times define the fundamental distribution function (the structural retardation spectrum) of the system or, equivalently, its fundamental material response function. These, together with a few experimentally measurable material constants, completely define the recovery behavior of the system when subjected to any thermal treatment. The behavior of the model is explored for various classes of thermal histories of increasing complexity, in order to simulate real experimental situations. The relevant calculations are based on a discrete retardation spectrum, extending over four time decades, and on reasonable values of the relevant material constants in order to imitate the behavior of polymer glasses. The model clearly separates the contribution of the retardation spectrum from the temperature-structure dependence of the retardation times which controls its shifts along the experimental time scale. This is achieved by using the natural time scale of the system which eliminates all the nonlinear effects, thus reducing the response function to the Boltzmann superposition equation, similar to that encountered in the linear viscoelasticity. As a consequence, the system obeys a rate (time) -temperature reduction rule which provides for generalization within each class of thermal treatment. Thus the model establishes a rational basis for comparing theory with experiment, and also various kinds of experiments between themselves. The analysis further predicts interesting features, some of which have often been overlooked. Among these are the impossibility of extraction of the spectrum (or response function) from experiments involving cooling from high temperatures a t finite rate; and the appearance of two peaks in the expansion coefficient, or heat capacity, during the heating stage of three-step thermal cycles starting a t high temperatures. Finally, the theory also provides a rationale for interpreting the time dependence of mechanical or other structure-sensitive properties of glasses as well as for predicting their long-range behavior.

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Stress and Volume Relaxation in Annealing Flat Glass

Cited by 161 publications

References 11 publications

Energy flow, partial equilibration, and effective temperatures in systems with slow dynamics

Energy flow, partial equilibration, and effective temperatures in systems with slow dynamics

Glass-Transition Temperature of Water: A Simulation Study

Isobaric volume and enthalpy recovery of glasses. II. A transparent multiparameter theory

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