A series of three sodium-potassium-silicate glasses with different alkali c
ontents were prepared. The glasses were exposed to a 50 keV electron bombar
dment of defocused beams of various current densities. Decay curves (alkali
X-ray intensity versus time) have been measured and analysed to obtain inc
ubation periods and maximum transport rates. Obtained data have been compar
ed with those known for binary alkali-silicate glass. The results confirm t
he influence of the mixed alkali effect on the transport behaviour of alkal
i ions under the electron bombardment. (C) 2001 Elsevier Science B.V. All r
ights reserved.