Structural relaxation of glassy GeSe2 during isothermal annealing below and above T g

Autor:	S. P. Timoshenkov, E. V. Aleksandrovich, V. S. Minaev
Rok vydání:	2015
Předmět:	Exothermic reaction Diffraction Materials science Physics and Astronomy (miscellaneous) Annealing (metallurgy) Thermodynamics Atmospheric temperature range Endothermic process law.invention symbols.namesake Differential scanning calorimetry law symbols Crystallization Raman scattering
Zdroj:	Technical Physics. 60:510-514
ISSN:	1090-6525 1063-7842
Popis:	Raman scattering, X-ray diffraction, and differential scanning calorimetry in the temperature range 300–800 K are used to show that, upon isothermal annealing of glass GeSe2 powders below the glass-softening temperature (Tg = 635 ± 2 K), fragments of high-temperature polymorphic modifications having no long-range order (HTPM polymorphoids) decompose and transform into low-temperature polymorphoids (LTPM) with an exothermic effect. A high concentration of LTPM polymorphoids in the glass and their stabilization upon annealing below Tg favor ordering and the appearance of coherent domains of low-temperature α-GeSe2 (3D form). Upon annealing above Tg, the reverse LTPM → HTPM polymorphoid transformation accompanied by an endothermic effect takes place, which results in the predominance of HTPM β-GeSe2 polymorphoids (2D form) in glassy GeSe2 and their crystallization.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8c43d3e39637893332dd1d489296bdb6 https://doi.org/10.1134/s1063784215040039 Zobrazit plný text záznamu Plný text ve formátu PDF