An-Najah Staff

From differential scanning calorimetry (DSC) measurements performed on Ge40S60 chalcogenide glass forming liquid, the values of the apparent activation energy Δh*, and the fragility index, m, as defined in the strong-fragile glass forming liquid concept, have been determined. The calculated value of m for this glass forming liquid is equal to 82. From this m value, it is suffice to conclude that this glass forming liquid belongs to an intermediate category that exhibits a kinetic behaviour between strong and fragile.
PACS: 61.43.Fs; 64.70.Pf; 65.60. +a

Differential scanning calorimetry measurements have been performed on elemental Se as well as on Ge_xSe_94−xIn₆ (x=4, 8, and 11 at%) and on Ge_ySe_88−yIn₁₂ (y=5, 7, and 9 at%) chalcogenide glasses. From the cooling rate dependence of the fictive temperature, the apparent activation energies, Δh*, and the fragility indices, m, as defined in the strong–fragile glass-forming liquid concept, are determined. It is found that, in Ge–Se–In system, there is an evolution from strong (m=67) to fragile (m=116) glass-forming liquids. The dependence of ‘m’ on the mean-coordination number, Z, is also obtained. This dependence is rationalized by assuming that, in this glassy alloy system, there is a tendency for the formation of In₂Se₃ clusters.