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Meeting experimental challenges to physics of network glasses: assessing role of sample homogeneity (1107.3901v2)
Published 20 Jul 2011 in cond-mat.dis-nn
Abstract: 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{\deg}C in high vacuum homogenize in 168 hours on a scale of 10{\mu}m. 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 ({\Delta}x < 0.6%). These abrupt elastic phase transitions are intrinsic to these materials and have a direct bearing on physics of glasses.