Atomistic model of physical ageing in Se-rich As–Se glasses

Abstract

Thermal, optical, X-ray excited and magnetic methods were used to develop a microstructural model of physical ageing in Se-rich glasses. The glass composition As₁₀Se₉₀, possessing a typical cross-linked chain structure, was chosen as a model object for the investigations. The effect of physical ageing in this glass was revealed by differential scanning calorimetry, whereas the corresponding changes in its atomic arrangement were studied by extended X-ray absorption fine structure, Raman and solid-state ⁷⁷Se nuclear magnetic resonance spectroscopy. Straightening–shrinkage processes are shown to be responsible for the physical ageing in this Se-rich As–Se glass.

Acknowledgements

The authors thank the US National Science Foundation, through the International Materials Institute for New Functionality in Glass (IMI-NFG), for initiating this international collaboration and providing partial financial support for the work (NSF Grant No. DMR-0409588). Special thanks are due to Dr S Khalid of X18B NSLS for useful discussions and help with the EXAFS measurements. M. Vlcek appreciates financial support from MSMT CR (project 0021627501).