TEM INVESTIGATIONS OF GLIDE LINES IN AMORPHOUS SILICA BELOW THE GLASS-TRANSITION

A previous SEM study has shown the occurrence of glide planes in deformed silica glass samples. The authors report TEM observations on the same samples. Ion beam milling produces a preferential thinning that reveals thin lines with a different spacing than traces of glide planes could have (image contrast is due to thickness absorption effects). In samples deformed at low temperature the lines are straight and parallel; for higher deformation temperature the lines begin to bend between anchoring points. It is propose that these lines correspond to glide fronts that have travelled in glide planes. Near the glass transition an undulation of a large path (about 0.2 μm) develops along the glide lines. It is suggested that this evolution is comparable to the Taylor instability.