Relaxation behavior of glassy selenium

Svoboda, Roman; Pustková, Pavla; Málek, Jiřı́

doi:10.1016/j.jpcs.2006.12.032

Cited by 42 publications

(42 citation statements)

References 18 publications

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“…36,37 An increase in the heating rate (γ T = 20 K/min) strongly increases the overshoot of the normalized specific heat, as observed in experiments, and shifts it towards higher temperatures. 36,37 It could also be remarked that, following the ratio of the cooling/heating temperature rates used, the model is able to reveal a decrease of the normalized heat capacity just before the overshoot. This effect, sometimes called "negative specific heat effect," is visible for the γ T = ±0.3 K/min protocol while not accessible for the γ T = −0.5 K/min and γ T = 20 K/min protocol.…”

Section: Configurational Specific Heatmentioning

confidence: 70%

Affinity and its derivatives in the glass transition process

Garden

Guillou

Richard

et al. 2012

The Journal of Chemical Physics

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The thermodynamic treatment of the glass transition remains an issue of intense debate. When associated with the formalism of non-equilibrium thermodynamics, the lattice-hole theory of liquids can provide new insight in this direction, as has been shown by Schmelzer and Gutzow [J. Chem. Phys. 125, 184511 (2006) (2011)]. Here, we employ a similar approach. We include pressure as an additional variable, in order to account for the freezing-in of structural degrees of freedom upon pressure increase. Second, we demonstrate that important terms concerning first order derivatives of the affinity-driving-force with respect to temperature and pressure have been previously neglected. We show that these are of crucial importance in the approach. Macroscopic non-equilibrium thermodynamics is used to enlighten these contributions in the derivation of C p ,κ T , and α p . The coefficients are calculated as a function of pressure and temperature following different theoretical protocols, revealing classical aspects of vitrification and structural recovery processes. Finally, we demonstrate that a simple minimalist model such as the lattice-hole theory of liquids, when being associated with rigorous use of macroscopic non-equilibrium thermodynamics, is able to account for the primary features of the glass transition phenomenology. Notwithstanding its simplicity and its limits, this approach can be used as a very pedagogical tool to provide a physical understanding on the underlying thermodynamics which governs the glass transition process.

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Section: Configurational Specific Heatmentioning

confidence: 70%

Affinity and its derivatives in the glass transition process

Garden

Guillou

Richard

et al. 2012

The Journal of Chemical Physics

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“…q ? = 1000°C s -1 cycle and the a-Se enthalpy relaxation TNM parameters [24][25][26]. The lower pair of curves corresponds to the cooling and the consequent heating step expressed by means of fictive temperature T f .…”

Section: Correct Data Preparationmentioning

confidence: 99%

“…6a, the chosen experimental FSC data obtained for a-Se [13] (dashed lines) are compared to the theoretically simulated data (solid lines). The simulation was performed for the same temperature histories as those of the FSC measurements; TNM model parameters determined for a-Se from the conventional DSC measurements [24][25][26] were input into the simulation (Dh * /R = 42.75 kK, ln(A/ s) = -133, b = 0.65, x = 0.52). As is apparent, there is a clear disagreement between the two datasets.…”

Section: Tnm Description Versus Thermal Gradientsmentioning

confidence: 99%

“…As is apparent, not even this new set of TNM simul. (a-Se, [24]) exp. data [13] DSC FSC q -= 1 °C min -1 q + = 10 °C min -1 q -= 100 °C s -1 q + = 1000 °C s -1 (a) (b) Fig.…”

Section: Tnm Description Versus Thermal Gradientsmentioning

confidence: 99%

“…The corrected experimental data (see ''Correct data preparation'' section, Fig. 4) were used as C N p , and the simulated relaxation signal (same temperature history as applied in the respective FSC experiment; true TNM parameters for a-Se glass [24][25][26]) was used as C pi . The temperature shift between the particular C pi curves was set to 1°C, and the maximum number of simulated curves was set to n = 75 (as will be shown later, this number was sufficiently high).…”

Section: Tnm Description Versus Thermal Gradientsmentioning

confidence: 99%

See 2 more Smart Citations

Glass transition kinetics measured by fast scanning calorimetry

Svoboda

2015

J Therm Anal Calorim

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Enthalpy relaxation data obtained for amorphous selenium by means of fast scanning calorimetry were described in terms of Tool-Narayanaswamy-Moynihan model. The effect of thermal gradients formed within the measured sample was found to explain the marked difference between the FSC and conventional DSC data obtained for a-Se. If the influence of thermal gradients is accounted for, the similar set of TNM parameters as obtained for a-Se from conventional DSC can be used to describe the FSC data. Temperature profiles of the thermal gradients as well as sources of additional uncertainties occurring within the introduced conception are discussed in detail. In addition, a normalization procedure accounting for the difference between the slopes of heat capacity in the glass and undercooled liquid regions was introduced. Correct data preparation was found to have a critical influence on the applied enthalpy relaxation evaluation procedures. Due to the unresolved issue of the prediction of manifesting thermal gradients found in case of the recent study on amorphous selenium, the FSC technique appears, for the time being, to have limited usage for enthalpy relaxation studies.

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Structural Relaxation near the Glass Transition: Observing Kovacs Kinetic Phenomenology by Mechanical Measurements

Guo

Bradshaw

2011

Time Dependent Constitutive Behavior and Fracture/Failure Processes, Volume 3

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Relaxation behavior of glassy selenium

Cited by 42 publications

References 18 publications

Affinity and its derivatives in the glass transition process

Affinity and its derivatives in the glass transition process

Glass transition kinetics measured by fast scanning calorimetry

Structural Relaxation near the Glass Transition: Observing Kovacs Kinetic Phenomenology by Mechanical Measurements

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