On the limitation of quantitative measurements using transmission electron microscopy

► Electron irradiation induced damage on CaF2 nanocrystals in silicate glasses has been demonstrated and interpreted. Unfortunately, the phenomena have been ignored in literature. ► The response of Na in silicate glasses to electron irradiation has been measured. The loss of Na induced glass structure change has also been discussed. ► It concludes that it is not appropriate to apply the advanced TEM/STEM techniques to silicate glasses containing alkali species.