Crack growth in borate and silicate glasses: Stress-corrosion susceptibility and hydrolytic resistance

A double cantilever beam technique in air equipped with ultrasound modulation was used to measure the crack velocity v in borate and silicate glasses. In all glasses v and the stress intensity K_I followed the empirical correlation v ~ K_Iⁿ. Indicated by its smallest K_I at v = 1 µm s ^{− 1}, K_I* = 0.27 MPa m^0.5, the silicoborate glass containing 70 mol% B₂O₃ was found most susceptible to stress-corrosion enhanced crack growth. Contrarily, the sodium calcium magnesium silicate glass appeared least susceptible with K_I* = 0.57 MPa m^0.5. No clear correlation is evident between K_I*, reflecting the stress-corrosion susceptibility, and the hydrolytic resistance for all glasses under study, but values of n obtained from the present study and taken from previous literature for 35 glasses tend to decrease with increasing network modifier ion fraction. Energy dissipation during stress-corrosion enhanced crack propagation is assumed to cause this trend.