Meeting experimental challenges to physics of network glasses: Assessing the role of sample homogeneity

Abstract

We introduce a Raman profiling method to track homogenization of Ge x Se 100− x melts in real time, and show that 2 g melts reacted at 950 °C in high vacuum homogenize in 168 h on a scale of 10μm. Homogenization of melts is precursive to self-organization of glasses. In the present glasses, compositional variation of Raman active corner-sharing mode frequency of GeSe 4 units, molar volumes, and the enthalpy of relaxation at T g , reveal the rigidity ( x c ( 1 ) = 19.5 ( 3 ) % ) and the stress ( x c ( 2 ) = 26.0 ( 3 ) % ) transitions to be rather sharp ( Δ x < 0.6 % ). These abrupt elastic phase transitions are in harmony with rigidity theory and have a direct bearing on the physics of glasses.