Reversibility window in as-quenched Ge-As-S glasses

Thermoanalytical characteristics and Raman scattering of high purity sulfur and ternary bulk glasses GexAsxS(100−2x) for x=4-22 at. % were studied. The intermediate phase characterized by vanishing of non-reversing heat flow ΔHnr, i.e. so-called the thermally reversing window was found between mean coordination number 〈r〉∼2.28-2.47. Separated phase of non-crystalline cycloocta-S, manifesting itself by λ-transition at ∼155 °C, was found for glasses with sulfur content higher than ∼80 at.%. Raman spectra of studied Ge-As-S glasses showed different shapes in three different areas according to three distinct phases of network glasses-floppy, intermediate, rigid.