Insights into the physical aging in chalcogenide glasses: A case study of a first-generation As2Se3 binary glass

The time-dependent variation in the physical properties is one of the most interesting and mysterious behaviors of melt-quenched disordered solids (like polymer glasses, metallic glasses, and especially in chalcogenide glasses). This phenomenon is recognized as physical aging which reveals that the asquenched glass stays in a meta-stable state (i.e., a thermodynamically non-equilibrium state) and so a thermally activated structural relaxation is the general characteristics of each glass as a consequence of natural or artificial physical aging (PhA). This review starts with the general introduction of PhA and its features. Different perceptive and peculiarities of PhA have been discussed keeping in mind the case of long-term PhA and anti-aging effects of arsenic in the chalcogenide glasses (ChGs) of the Se-As system. Further, we have reported the case study of As2Se3 stoichiometric glass and the results of some new observations during the natural aging of the Arsenic Tri-Selenide glass (g-As2Se3). The thorough inspection of PhA effects in this industrial glass is done after storing at ambient temperature in a glovebox for ten years. Thermal analysis is done by using differential scanning calorimetry. The XRD and TEM/SEM techniques have been employed for structural analysis. The information of various kinds of bonding is acquired by using Raman spectroscopy. Also, we have determined the thermal stability parameter, Vickers hardness, compactness, fragility, and density of the fresh and old samples of As2Se3 glass to see the consequences of PhA. Finally, the new advances and present status related to the studies of PhA have been discussed. (C) 2021 Elsevier B.V. All rights reserved.