Connectivity and glass transition in disordered oxide systems

Ojovan, Michael I.; Lee, William

doi:10.1016/j.jnoncrysol.2010.05.012

Cited by 61 publications

(75 citation statements)

References 43 publications

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“…Many key properties of glasses are dependent on the connectivity of the network, as it accounts for the differences in energy between glasses and crystals [21]. Generally, in glasses only the short-range structure is well defined, whereas structure in the intermediaterange remains a topic for discussion [22,23].…”

Section: Network Connectivity Analysismentioning

confidence: 99%

Predicted structure, thermo-mechanical properties and Li ion transport in LiAlF4 glass

Stechert

Rushton

Grimes

et al. 2012

Journal of Non-Crystalline Solids

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Section: Network Connectivity Analysismentioning

confidence: 99%

Predicted structure, thermo-mechanical properties and Li ion transport in LiAlF4 glass

Stechert

Rushton

Grimes

et al. 2012

Journal of Non-Crystalline Solids

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“…This is a form of collective action of excitations which lead to qualitative changes in the system e.g. similar to those which occur in a system of broken bonds in an amorphous material [27]. In contrast to single excited atoms the lifetime of condensed RM can be very long of the order of seconds to hours depending on the principal quantum-mechanical level of excitation.…”

Section: Discussionmentioning

confidence: 95%

Rydberg Matter Clusters: Theory of Interaction and Sorption Properties

Ojovan

2011

J Clust Sci

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Sorption capacity of Rydberg matter (RM) clusters is examined for both electronegative and neutral molecules. Sorption isotherm of RM has been determined as a function of gas pressure and time. It is shown that chemisorption is characteristic for electronegative molecules whereas molecules with no affinity to electrons are absorbed by physisorption mechanism. Sorption capacity of RM is shown to be highest for physisorption mechanism. Absorption of molecules by RM clusters can be used either to detect condensed RM formation or both to maintain high vacuum conditions and high purity of noble gas atmospheres. Sorption capacity of RM can significantly exceed conventional getter sorption capacities.

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“…Note that for some materials this value belongs to the glasstransition region defined by specific heat capacity measurement, but it is not the case for other materials [9]. A significant interest is also seen to study the viscous flow [1,[7][8][9][10][11][12][13][14]. The activation energy of viscous flow of amorphous materials Q (T) is nearly constant in the two asymptotic cases -at low temperatures when the material is in the glassy state, and at high temperatures, when the material is in a state of true melt.…”

Section: Introductionmentioning

confidence: 99%

About activation energy of viscous flow of glasses and melts

Ojovan

2015

MRS Proc.

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Data on a viscous flow model based on network defects -broken bonds termed configurons -were analysed. An universal equation has been derived for the variable activation energy of viscous flow Q(T) of the generic Frenkel equation of viscosity η(T)=A·exp(Q/RT) which is known to have two constant asymptotes -high Q H at low temperatures and low Q L at high temperatures. The defect model of flow used by e.g. Doremus, Mott, Nemilov, Sanditov states that higher the concentration of defects (e.g. configurons) the lower the viscosity. We have used the configuron percolation theory (CPT) which treats glass-liquid transition as a percolation-type phase transition. Additionally the CPT results in a continuous temperature relationship for viscosity valid for both glassy and liquid amorphous materials. We show that a particular result of CPT is the universal temperature relationship for the activation energy of viscous flow: Q(T)=Q L +RT·ln[1+exp(-S d /R) exp((Q H -Q L )/RT)] which depends on asymptotic energies Q L (for the liquid phase) and Q H (for the glassy phase), and on entropy of configurons S d . This equation has two asymptotes, namely Q(T<>T g ) = Q L . Moreover we demonstrate that the equation for Q(T) practically coincides in the transition range of temperatures with known Sanditov equation.

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Connectivity and glass transition in disordered oxide systems

Cited by 61 publications

References 43 publications

Predicted structure, thermo-mechanical properties and Li ion transport in LiAlF4 glass

Predicted structure, thermo-mechanical properties and Li ion transport in LiAlF4 glass

Rydberg Matter Clusters: Theory of Interaction and Sorption Properties

About activation energy of viscous flow of glasses and melts

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