Internal friction and relaxation mechanism of F-doped SiO2 glasses

The internal friction and the Young's moduli of pure SiO2, SiO2-4 mol% F an d -8 mol% F glasses were measured in the temperature range of 1.6-250 K. Th e temperature dependencies of the internal friction were not different exce pt for their peak values, which showed differences of a few percent at 35 K . In contrast, the Young's moduli of F-doped SiO2 glasses were 7.5% (-4 mol % F) and 15% (-8 mol% F) less than that of pure SiO2 glass, respectively. B oth temperature dependencies were analyzed on the basis of Debye relaxation by the distributed double-well potential model. (C) 1999 Elsevier Science B.V. All rights reserved.