Dehydroxylation and formation of KU-1 silica glass surface defects during annealing

• Published in: Moscow University chemistry bulletin Vol. 65; no. 1; pp. 34 - 37
• Main Authors: Lunin, B. S., Kharlanov, A. N., Kozlov, S. E.
• Format: Journal Article
• Language: English
• Published: Heidelberg Allerton Press, Inc 01.02.2010
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; silica glass; annealing; dehydroxylation
• ISSN: 0027-1314; 1935-0260
• DOI: 10.3103/S0027131410010049

Formation of KU-1 silica glass surface defects under annealing is considered. Based on experimental data obtained by annealing of silica glass samples in the temperature range of 800–980°C, it is shown that internal stress forming due to dehydroxylation of the surface zone is the main cause of surface defects. To determine the depth of this zone for different annealing conditions, a formula is suggested. It shows that the internal stress is less than the critical one and the silica glass surface is not changed if the annealing temperature is 850°C or higher due to the fast relaxation rate. At a lower annealing temperature, the surface defects are formed in a few tens of hours during annealing.