Electron energy loss spectroscopy of Na in Na, Na₂O, and silicate glasses

Measuring Na in silicate glasses can be difficult in transmission electron microscopy due to modifications induced by electron irradiation. The modifications involve not only the loss of Na from the illuminated region, but also the formation of Na and Na₂O. This work compares the electron energy loss spectroscopy (EELS) of plasmon and Na L₂₃ edge in Na₂O–SiO₂ glass with those in Na and Na₂O. The interpretations of the fine structures in Na L₂₃ edge were also given with the aid of full multiplescattering calculations. It demonstrates that the formation of metallic Na can be easily identified by its bulk plasmon at about 5.8 eV, and the formation of Na₂O can be better seen by Na L₂₃-edge fine structure.