The annealing characteristics of Knoop-indented silica and soda-lime-silica glasses were investigated. These glasses were indented using a Knoop indenter in water, and they were annealed at various temperatures below the glass transition temperature. The major diagonal length of the Knoop indentation was measured before and after annealing, and the change of the diagonal length was determined. The change of diagonal length in silica glass was much larger than that in soda-lime-silica glass. This was attributed to the occurrence of more densification around the Knoop indentation in the silica glass. The activation energy of the shrinkage of the Knoop indentation in the silica glass, estimated from the temperature dependence of the relaxation time, was 46 kJ/mol, which was much less than that of viscous flow in silica glass.
