Strengthened glass articles with reduced delayed breakage and methods of making the same

A method of strengthening glass articles includes introducing potassium ions to a surface region of the glass by an initial ion-exchange process, thermally treating the glass at a thermal treatment temperature and time sufficient to diffuse the potassium ions further into the glass to a depth of layer, and introducing a compressive stress of greater than 400 MPa at the surface through a final ion-exchange process. The final ion-exchange process may be conducted at a final ion-exchange temperature of no more than 450° C. The method of strengthening produces a glass article having a compressive stress of at least 400 MPa at the surface, a depth of compression of at least 30 μm, and a central tension less than a threshold central tension above which flaws penetrating into the central region of the glass exhibit spontaneous self-propagation of the flaw front through and across the glass.