Effect of humidity on crack healing in glass from in-situ investigations using an ESEM

In-situ healing of Vickers indentation cracks in soda-lime-silicate glass was observed using an environmental scanning electron microscope (ESEM). The change in crack length as a function of time and temperature was studied. The effect of the initial humidity level on the crack healing behavior was also investigated in-situ by varying the initial temperature of the specimen and the ESEM specimen chamber pressure. The crack healing results were fit to an equation previously used to describe thermal and mechanical fatigue crack behavior in ceramics.