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Publikace detail

Heat capacity of vitreous GeS2
Autoři: Málek Jiří | Chovanec Jozef | Svoboda Roman | Taniguchi Y. | Kawaji H.
Rok: 2015
Druh publikace: článek v odborném periodiku
Název zdroje: Journal of Chemical Thermodynamics
Název nakladatele: Academic Press (Elsevier)
Místo vydání: LONDON
Strana od-do: 101-108
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Tepelná kapacita skelného GeS2 Tepelná kapacita skelného GeS2 byla měřena v rozsahu od 2 do 600 K několika metodami: relaxační metodou, adiabatickou kalorimetrií a diferenciální skenovací kalorimetrií. chalkogenidová skla; tepelná kapacita; GeS2
eng Heat capacity of vitreous GeS2 The heat capacity for GeS2 glass was measured by relaxation method, adiabatic calorimetry and DSC from T/K = (2 to 600). Values of the standard molar enthalpy and the standard molar entropy are 12.713 kJ.mol(-1) and 88.46 J.K-1.mol(-1), respectively. The molar heat capacity data for GeS2 glass were compared with those reported previously for crystalline alpha-GeS2. The molar heat capacity of the glass is higher than of the crystal above T = 75 K. However, the molar heat capacity of the glass is lower than that of crystal in the temperature range between (23 and 70) K. This anomaly can probably be attributed to structural differences between vitreous and crystalline state considering that the medium range order of the germanium sulfide glass is similar to that of the crystalline polymorph alpha-GeS2 although the dimensionality of network is probably higher than 2D. The heat capacity of GeS2 glass obtained by quenching from equilibrium liquid at T = 1270 K is higher than that of the glass resulting from quenching from metastable supercooled liquid within the glass transition range (about 0.2% for 100 < T/K < 200 and 0.4% at T = 50 K). This proves that parameters defining thermal history of the glass (i.e. cooling rate and initial temperature) may affect the value of heat capacity. Chalcogenide glasses; Heat capacity; GeS2