K. Matusita et al., VISCOUS-FLOW MECHANISM OF OXYFLUORIDE GLASSES RELATED TO GLASS STRUCTURE, Journal of non-crystalline solids, 177, 1994, pp. 216-220
The viscosities of 30PO.(70-x)SnF2.xSnO glasses were measured over a w
ide temperature range, and the viscous now mechanism is compared with
those of silicate and fluoride glasses. It was found that the viscosit
y and activation energy decrease as the concentration of fluoride ions
increases. The viscosity can be expressed by the Fulcher equation ove
r a wide temperature range except for the glass of the low fluorine co
ntent. Sn2+ ions are thought to play the role of network modifiers and
the viscous now behavior is determined by weak Sn-F and P-F bonds.