Diffusion in glasses

Teoh, H.M., Schmidt, SJ., Day, G.A., and Faller, J.F. 2001. Investigation of commeal components using dynamic vapor sorption and differential scanning calorimetry. J. Food Sci. 66, 434-440. Tromp, R.H., Parker, R., and Ring, S.G. 1997. Water diffusion in glasses of carbohydrates. Carbo-hydr. Res. 303, 199-205. 

Doremus, R. H. 1977a. Diffusion in glasses and melts. Journal of Non-Crystalline Solids, 25, 261-292. 

R. Kirchheim. Interstitial diffusion in glass. Defect and Diffusion Forum, 95-98 1159-1164, 1993. 

R. Kirchheim. Interstitial diffusion in glasses and the mixed alkali effect. In H. Jain and D. Gupta, editors, Diffusion in Amorphous Materials, pages 43-54, Warrendale, PA, 1994. The Minerals, Metals and Materials Society. 

Perhaps the best approach to this problem lies in the study of inert gas solubility and diffusion in glasses. Inert gas atoms can be used as probes of the interstitial regions of glasses. It is also possible that computer simulations of glass structures will aid in understanding the empty space which we all know must exist in these network structures. In any case, it is certain that a full understanding of the structure of a glass has not been obtained until we can confidently predict such basic properties as the density. 

In theory, diffusion coefficients can be measured for any ion. In practice, however, most studies of ionic diffusion in glasses have been restricted to highly mobile ions which have a convenient radioactive isotope for use in tracer measurements. As a result, a majority of the data for ionic diffusion deals with sodium, with lesser amounts of data for potassium, rubidium, and cesium. Studies of lithium are very limited due to the lack of a radioactive isotope of lithium, while studies of divalent and other, more highly charged, ions are restrieted by the very low mobilities of these ions as compared to those of the monovalent ions. 

Tsekhosmski, V. A., Mazurin, O. V., and Evstrop ev, K. K. (1963) Nature of the Conduetivity of Alumino-silieate Glasses, Sou. Phys. - Solid State, 5, 426-428. LaCourse, W. C. (1976) Structural Influences on Diffusion in Glass - The Mixed Site Effeet, J. Non-Cryst. Solids, 21, 431-434. 

Proton diffusion in glass induces cracks in the same way as occurs on substitution of Na and by Li ions which implies that large H30 ions are not formed. In fact, 0 and diffusion measurements show that proton diffuses 100 times faster than oxygen . This supports the assumption that the diffusion mechanism consists also of proton jumps and not only of OH jumps. The corresponding activation energy has... 

Soules TF (1982) Molecular dynamic calculation of glass stmcture and diffusion in glass. J Non-Cryst Sol 49 29-52... 

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