Proportional counting (beta rays) with considerable self-absorption and scintillation counting (gamma rays) with negligible self-absorption, were found to yield essentially the same results. It was found experimentally that the self-absorption of the beta radiation could be represented by a Beer-Lambert type law. For the glass, 27Na2O-3Al2O3-70SiO2, the results were described by:

D(cm2/s) = 2.96 x 10-4 exp[-13.7(kcal/g-ion)/RT]

at 228 to 436C. For 11Na2O-18Al2O3-71SiO2,

D(cm2/s) = 5.02 x 10-4 exp[-14.5(kcal/g-ion)/RT]

at 352 to 716C.

H.M.Garfinkel, H.E.Rauscher: Journal of Applied Physics, 1966, 37[5], 2169-74