Strengthening of borosilicate glass by ion exchange for advanced ballistic impact behaviour

Borosilicate glass was reinforced via ion exchange to improve the ballistic impact resistance of transparent bulletproof materials. The optimal heat treatment conditions of ion-exchanged borosilicate glass with thicknesses of 4, 6 and 8 mm were 12, 15 and 17 min at 560 degrees C, respectively. The flexural strengths of the reinforced glasses were 0.783 +/- 0.018, 0.810 +/- 0.014 and 0.835 +/- 0.013 GPa, respectively. This improved on that of the parent material by a factor of 2.5. Light transmittance exceeded 91.1%. The bulletproof materials comprised one polycarbonate sheet, two multilayer defence films and strengthened glass. The thickness of the bulletproof material decreased by similar to 18%, from 28.80 mm for the original glass to 23.65 mm for the strengthened glass. The ballistic limit velocity improved by 14% from 851 (V-50) to 972 (V-0) m/s. The light transmittance of the material was 86.2%, confirming its potential use as a transparent bulletproof material.