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Publikace detail

Kinetic fragility of Se-based binary chalcogenide glasses
Rok: 2015
Druh publikace: článek v odborném periodiku
Název zdroje: Journal of Non-Crystalline Solids
Název nakladatele: Elsevier Science BV
Místo vydání: Amsterdam
Strana od-do: 39-44
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Kinetická fragilita selenových binárních chalkogenidových skel Kinetická fragilita byla stanovena pro řadu složení skel systémů Ge-Se, As-Se a Te-Se. Hodnoty fragility byly získány z viskozitních a entalpicko-relaxačních dat. kinetická fragilita; chalkogenidy; viskozita; entalpická relaxace; odchýlení
eng Kinetic fragility of Se-based binary chalcogenide glasses Kinetic fragility was determined for a number of compositions from the Ge-Se, As-Se and Te-Se chalcogenide glassy systems. Values of fragility indices were evaluated from both viscosity and enthalpy relaxation data. Comparison of the viscosity and enthalpy fragilities shows marked decoupling in cases of low-Ge/As-content compositions and the whole Te-Se glassy system. A possible explanation regarding the increased viscosity fragilities involves the influence of dynamic structural heterogeneity (density fluctuations and clustering of structural elements) on shear viscosity in the glass transition region. In particular, the observed decoupling seems to occur in case of the materials exhibiting moderate-to-high activation energy of relaxation processes and large structural cooperativity. The origin of the fragility decoupling may lie either in different molecular movements being involved in the two processes (viscous flow versus structural relaxation) or in their different manifestation in terms of volume and enthalpy behavior. Kinetic fragility; Chalcogenides; Viscosity; Enthalpy relaxation; Decoupling