Fragility of chalcogenide glass in relation to characteristic temperature T0/Tg

Autor: K. Venkataraman, T. Lilly Shanker Rao, T. Shanker Rao, A. M. Shaker
Rok vydání: 2018
Předmět:
Zdroj: IOP Conference Series: Materials Science and Engineering. 330:012004
ISSN: 1757-899X
1757-8981
Popis: The present study reports the mutual relationship between the fragility index m and the characteristic temperature T0/Tg. The fragility of the chalcogenide amorphous glass of Ge10Se50Te40 is calculated by utilizing glass transition temperature (Tg) measured by DSC (Differential Scanning Calorimetry) at different heating rates (β) in the range 5 to 20 K/min. Vogel-Fulcher-Tammann (VFT) equation is fitted to the data of Tg. In addition to the VFT method, three other methods are also used to evaluate m. The fragility index m of the Ge10Se50Te40 system showed the trend of decrease with increasing heating rate but remained stable around 22 for the heating rate 10 K/min. The value of m for the glass is near the lower limit (m ≈ 16) this indicates the alloy is a strong glass forming material in accordance of Angell's interpretation of fragility. The calculated values of characteristic temperature T0/Tg is very close to 1 which also indicates that clearly the system is most fragile.
Databáze: OpenAIRE