Molecular structure of virgin and T$_{g}$ cycled (Ag$_{2}$Se)$_{x}$ (AsSe)$_{1-x}$ bulk glasses

AsSe, the base glass (x = 0) in the titled ternary, is an interesting example of a chalcogenide that is partially de-mixed into As$_{4}$Se$_{4}$ molecules segregated from a connected AsSe network, with the latter determining glass network properties. Raman scattering reveals sharp modes of the Realgar molecules that are superimposed on broad modes coming from of the backbone. Upon T$_{g}$ cycling virgin samples (as quenched melts), the concentration of de-mixed As$_{4}$Se$_{4}$ molecules decreases, suggesting that thermally induced polymerization occurs; molecules break up to form part of the connective tissue. Modulated DSC experiments reveal a broad exotherm near 140 $^{\circ}$C in virgin samples, which becomes nearly extinct in T$_{g}$ cycled samples. The exotherm may represent Realgar molecules nano-crystallizing as the temperature approaches T$_{g}$. Compositional trends in thermal parameters such as T$_{g}$(x), $\Delta $C$_{p}$(x), and the $\Delta $H$_{nr}$(x) as a function of Ag$_{2}$Se content `x' of the glasses will be reported.