Structural relaxation due to sub-Tg annealing of Se98In1.5Sn0.5 chalcogenide glass

Aging in chalcohalide glasses: Origin and consequences

“…According to DSC measurements on asprepared and physically aged samples, T f decreases upon aging. In detail, T f of the as-prepared glass is 660 K, whereas that of the glass aged in Ar for 48 h at 0.95T g is 643 K. The decrease of T f upon aging agrees with previous findings [15,27]. However, this H V -T f relation is contrary to that of most oxide glasses [28,29].…”

Understanding Glass through Differential Scanning Calorimetry

“…Chalcogenide glasses are generally composed of covalently bonded rings, chains, layers, and three-dimensional structures, with van der Waals forces acting between structural units. The glass transition temperature T g of chalcogenide glasses is generally lower compared to that of oxide glasses. , This means that the enthalpy relaxations in these glasses can occur more easily compared to oxide glasses, particularly at low temperatures. By conducting TMDSC experiments, Lucas et al , have studied the photoinduced structural relaxations in both the Ge-Se and As-S-Se glass systems during sub-bandgap irradiation.…”

“…A systematic study on the enthalpy relaxation in the Ge x ·Se 1– x glasses was carried out by Saiter’s group regarding the effect of the degree of annealing and the composition on the enthalpy relaxation. − Similar to the As x Se 1– x glasses, the Ge x Se 1‑ x glasses and the Se 98 In 1.5 Sn 0.5 glass exhibit an increase of T g with increasing T a and/or t a . This further confirms that the sub- T g annealing induced the α relaxation in the Se-based chalcogenide glasses.…”

“…The heat capacity C p of the annealed HQ glasses provides access to the different microstructural regions associated with different relaxation time scales. If the annealing temperature is sufficiently high (but below T g ) or the annealing time is sufficiently long, the occurrence of the endothermic prepeak prior to the sub- T g energy release peak, which can be eliminated by a second upscaning, is a common phenomenon of the fragile oxide glasses, ,,,, metallic glasses, , polymer glasses, and chalcogenide glasses. ,− The endothermic prepeak is attributed to the fast-relaxing regions with high potential energy, implying the existence of the structural heterogeneity of the glass or the supercooled liquid at T f . In particular, the endothermic prepeak is a reflection of the nonexponential nature of the relaxation in systems far from equilibrium .…”