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

摘要

We introduce a Raman profiling method to track homogenization of Ge _xSe_(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 ~(Tg), reveal the rigidity (~(xc)(1)=19.5(3)) and the stress (~(xc)(2)=26.0(3)) transitions to be rather sharp (Δx<0.6). These abrupt elastic phase transitions are in harmony with rigidity theory and have a direct bearing on the physics of glasses