Paper detail

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

We introduce a Raman profiling method to track homogenization of Ge$_x$Se$_{100-x}$ melts in real time, and show that 2 gram melts reacted at 950°C in high vacuum homogenize in 168 hours 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 intrinsic to these materials and have a direct bearing on physics of glasses.