Effect of Etched Depth on Glass Strength

Studies of fracture strength of abraded and as‐received glass tubes as a function of etching depth showed that at depths less than the calculated initial flaw depth (∼50 μm) the strength increase was almost entirely due to reduction inflow depth from etching. This result is consistent with model 1 proposed by Proctor; it disagrees with his interpretation of his own results, no doubt because his study focused on etching depths of ≥100 μm.