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Viscosity of chalcogenide glass-forming liquids: an anomaly in the ‘strong’ and ‘fragile’ classification

1996; Elsevier BV; Volume: 197; Issue: 2-3 Linguagem: Inglês

10.1016/0022-3093(95)00628-1

1873-4812

Udayan Senapati, Arun K. Varshneya,

Glass properties and applications

High purity chalcogenide glasses with an average coordination number, 〈r〉, between 2 and 2.8 were prepared by vacuum melting of pre-distilled samples in the GeSe binary and GeSbSe ternary systems. Viscometry and scanning calorimetry were performed to understand the nature of the property thresholds observed with respect to 〈r〉 in these glass-forming systems. There is a lack of correlation between viscosity-based and heat capacity-based classifications of strong and fragile liquids in the overconstrained region of these glass-forming systems. An argument based on Adam-Gibbs equation and mode decoupling is put forward for the observation of the anomaly.