The topology of crack tips in soda-lime-silicate glass was investigated using atomic force microscopy (AFM). Studies were conducted on cracks that were first propagated in water and then subjected to stress intensity factors either at or below the crack growth threshold. Exposure to loads at the crack growth threshold resulted in long delays to restart crack growth after increasing the stress intensity factor to higher values. After breaking the fracture specimen in two, the "upper" and "lower" fracture surfaces were mapped and compared using AFM. Fracture surfaces matched to an accuracy of better than 0.5nm normal to the fracture plane and 5nm within the fracture plane. Displacements between the upper and lower fracture surfaces that developed after a critical holding time were independent of distance from the crack tip, & increased with holding time.
