Revealing the nature of glass by the hyperquenching-annealing-calorimetry approach

• Published in: Journal of non-crystalline solids. X 2022-06, Vol.14, p.100099, Article 100099
• Main Author: Yue, Yuanzheng
• Format: Article
• Language: English
• Subjects: Calorimetry; Energy bird; Fragile-to-strong transition; Glass; Hyperquenching; Shadow glass transition; Structural heterogeneity; Sub-Tg annealing
• ISSN: 2590-1591; 2590-1591
• DOI: 10.1016/j.nocx.2022.100099

C. Austen Angell has been a great inspiration for liquid and glass scientists including myself. He was a close collaborator of mine on glass dynamics and thermodynamics, particularly on the sub-Tg relaxation in glass. Here, in memory of his seminal contributions to science and our collaboration, I revisit our published data and analyze our unpublished data, as well as review some of important results reported recently in the literature, concerning the sub-Tg relaxation in glass, a field on which Austen has profoundly impacted. I highlight new insights into the dynamics, thermodynamics, and structural heterogeneity in glass far from equilibrium, based on the hyperquenching-annealing-calorimetry (HAC) experiments. I describe key extensions and applications of the HAC approach in glass research. Finally, I present the perspectives and challenges regarding the sub-Tg relaxation in glasses with fictive temperatures well above Tg. •The hyperquenching-annealing-calorimetry approach is used to solve glass problems.•The above-mentioned approach is named the ‘energy bird’ approach.•The ‘energy bird’ proved to be very sensitive to structural heterogeneity in glass.•The origin of the ‘shadow’ glass transition is discussed through literature data.