Vitreous silica melted under a reducing atmosphere initially contains approximately 160ppm wt of hydroxyl and an equal amount of Si-H. Both species can be removed by heat treatment at >700 deg C. Complete removal of hydroxyl and hydride only occur if the heat treatment is performed in a hydrogen-free atmosphere. Removal of both species can be treated as a diffusion process, with an activation energy of 278 kJ/mol.
Origin
Alfred University, Usa
Journal Title
Proc Xviii Icg, San Francisco, Usa, July 1998 159-164
Sector
Special Glass
Class
S 1855