Quantitative methods for electron microprobe analysis of sodium in natural and synthetic glasses

Two methods have been developed for the microprobe analysis of Sodium in natural and synthetic glasses that exhibit time-dependent element migration during electron bombardment. A cryogenic method is based on the cooling of the sample to -90oC at which temperature sodium diffusion rate from the excitation volume is reduced to z€ro. An empirical correction method determines the shape of the sodium decay curve as a function of time during electron bombardment, which under normal operating conditions, gives initial sodium concentration by extrapolation.