SOLUBILITY AND DIFFUSIVITY OF ARGON IN VITREOUS SILICA

Saturation of vitreous silica fibers by argon gas has provided solubility and diffusivity data in good agreement with previous experimental and modeling studies. Over the temperature range of 525-675-degrees-C, the solubility of argon in vitreous silica can be given by S = (2.09 x 10+21 atoms/(m3 atm)) exp((+ 31.5 kJ/g atom)/RT). These data indicate that the density of interstitial solubility sites accessible to argon atoms is 1.1 x 10(26) m-3, consistent with the log-normal model of interstitial site size distribution, a useful illustration of medium-range glass structure. Over the temperature range of 500-905-degrees-C, the diffusivity of argon in vitreous silica can be given by: D = (0.506 x 10(-8) m2/s) exp((- 113 kJ/g atom)/RT).