The diffusion of Cs+, Rb+, and K+ ions was measured in three grades of vitreous SiOl by the radiotracer-sectioning technique or Rutherford ,backscattering spectroscopy. The values of the diffusion coefficient, D , at 1000°C decrease strongly with increasing ionic radius, changing by about two and one-half orders of magnitude per row of the periodic table. The difference between Dcs and DRb is largely in the preexponential factor Do in the Arrhenius expression rather than in the activation enthalpy Q . The values of D are much smaller than the tracer D values for the alkali metal ion in homogeneous Rb or Cs silicate glasses. Residual metallic impurities in the Si02 decrease both Q and Do for the diffusion of Rb. The results are analyzed in terms of the interstitial structure of vitreous SO2.

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Im Hinblick auf die vorgeschlagene Einkapselung (Lagerung) von radioaktiven Abfällen in Gläsern wurde die Diffusion von Cs+, Rb" und K+ in glasigem SiO2 (geschmolzenem Quarz) durch Radiotracer‐Sectioning (mCs, 8°C Rb, 42K) und Rutherford‐Rückstreuspektroskopie (2.9‐MeV‐4He ) gemessen.