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analogous coefficients and uncover some generalized correlations between glass-forming ability (GFA) and glass stability (GS). Glass-forming ability and GS Glass is a specific matter reflecting its original liquid makeup and can

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Abstract  

The glass formation and devitrification of GaF3-based glasses were studied by differential scanning calorimetry. A comparison of various simple quantitative methods to assess the level of stability of multicomponent fluoride glass systems is presented. Most of these methods are based on critical temperatures. In this paper a new parameter k b(T) is added to the stability criteria. The stability of several GaF3-based glasses were experimentally evaluated and correlated with the activation energies of crystallization via this new kinetic criterion and compared with those evaluated by other criteria.

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Abstract  

The present paper reports on the effect of MoO3 on the glass transition, thermal stability and crystallization kinetics for (40PbO–20Sb2O3–40As2O3)100−x–(MoO3)x (x = 0, 0.25, 0.5, 0.75 and 1 mol%) glasses. Differential scanning calorimetry (DSC) results under non-isothermal conditions for the studied glasses were reported and discussed. The values of the glass transition temperature (T g) and the peak temperature of crystallization (T p) are found to be dependent on heating rate and MoO3 content. From the compositional dependence and the heating rate dependence of T g and T p, the values of the activation energy for glass transition (E g) and the activation energy for crystallization (E c) were evaluated and discussed. Thermal stability for (40PbO–20Sb2O3–40As2O3)100−x–(MoO3)x glasses has been evaluated using various thermal stability criteria such as ΔT, H r, H g and S. Moreover, in the present work, the K r(T) criterion has been considered for the evaluation of glass stability from DSC data. The stability criteria increases with increasing MoO3 content up to x = 0.5 mol%, and decreases beyond this limit.

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Thermal properties of oxide glasses

Part III. Thermal stability of Li2O·2SiO2·nMeO2 glasses (M=Ti, Zr)

Journal of Thermal Analysis and Calorimetry
Authors: P. Šimon, E. Jóna, and V. Pavlík

Abstract  

Glasses with the composition Li2O·2SiO2·nTiO2 and Li2O·2SiO2·nZrO2, where n=0, 0.03, 0.062, 0.1, were prepared and the onset and peak temperatures have been determined by DTA. From these characteristic temperatures, the kinetic parameters describing the nucleation and crystal growth have been obtained by isoconversional methods. The kinetic parameters have been used for the calculation of nucleation and crystal growth times for individual glasses so determining the order of glass stability at reheating. The stability of glasses increases with the content of TiO2 or ZrO2 where the increase is higher for ZrO2. Within the concentration range under study, the increase of both times with the metal oxide concentration is quadratic. It has been discussed that the crystallization kinetics does not obey the Arrhenius law and, therefore, when using the evaluation methods based on this law, the results should not be extrapolated outside the temperature range of the measurements.

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Thermal properties of oxide glasses

Part IV. Induction period of crystallization as a criterion of thermal stability of M2OSiO2 (M = Li, Na) glass systems against crystallization

Journal of Thermal Analysis and Calorimetry
Authors: S. Lendvayová, K. Moricová, E. Jóna, J. Kraxner, M. Loduhová, V. Pavlík, J. Pagáčová, and S. C. Mojumdar

). Several authors [ 8 , 9 ] suggested that the crystallization activation energy could also be used to evaluate the glass stability, but criteria based on the activation energy, or crystallization rate constants do not always fit with the actual

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The values of thermal stability were established by relation: K H = ( T c − T g ∗ )/( T m − T c ); where K H is Hruby parameter of glass stability [ 10 ]. The compositional dependency K H of glassy samples is presented in Fig. 8 for both

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obvious advantage of this method is that it can evaluate the glass stability over a broad temperature range other than at only one temperature such as T g or T p . Experimental Bulk chalcogenide Sb x Ge 25− x Se 75 (0 ≤ x

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. Soliman , AA , Kashif , I 2010 Copper oxide content dependence of crystallization behavior, glass forming ability, glass stability and fragility of lithium borate glasses . Phys B 405 : 247 – 253 10.1016/j.physb.2009

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temperature, T c , peak temperature, T p , flow temperature, T f , criterion of glass stability, T c − T g , of (100 − x )[0.5ZnO–0.1B 2 O 3 –0.4P 2 O 5 ]– x TeO 2 glasses and survey of crystalline products identified by XRD in the samples annealed at

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lowest for 60B 2 O 3 –40Bi 2 O 3 , indicating that 60B 2 O 3 –40PbO is more thermally stable . It was previously reported that the higher Bi 2 O 3 content of the alloy, the lower its glass stability [ 25 – 27 ]. Table 1

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