Effects of SrO/ZnO on structure and properties of UV-transmitting borophosphosilicate glass

UV-transmitting borophosphosilicate glasses series, 2Al2O3−xSrO-(18−x)ZnO-33.3P2O5-16.7B2O3-30SiO2 glasses with x=0-18 mol% were prepared and studied. The substitution of SrO for ZnO increases the density and the thermal expansion coefficient (α), but decreases the molar volume (Vm). The glass transition temperatures (Tg) and softening points (Td) vary within a small range. The relative chemical durability was determined by measuring the weight loss of a polished glass sample after immersion in deionized water at 50 °C for 24 h, the chemical durability of the glasses increases when x≤9, and drops when x>9. With the increasing SrO content, the UV transmittance of the glasses decreases mildly. The compositional dependence of Eopt shows a decrease trend with increasing SrO content. The structural changes with the glass compositions were examined by FT-IR and Raman spectra.