Effect of modifiers field strength on optical, structural and mechanical properties of lanthanum borosilicate glasses

An attempt has been made to understand the role of modifiers on physical, mechanical and spectroscopic properties of AO-SiO2-B2O3-La2O3. (A=Mg, Ca, Sr, Ba) glasses. The replacement of alkaline earth metals which act as modifier in glass matrix exhibit, marked difference in their strength and optical properties. The results are discussed in light of non-bridging oxygens (NBO), optical basicity, refractive index, polarisability, hardness and fracture toughness. In addition to this, Weibull statistics and cumulative probability of failure have also been analyzed. Band gap of glasses has been calculated using UV-visible spectroscopy where the variation in band gap is observed to increase with the addition of heavier modifier. Raman features have been explored for all prepared samples through Raman spectra which is in agreement with Fourier transform infra-red (FTIR) spectroscopy and Fourier transform nuclear magnetic resonance (FTNMR). (C) 2012 Elsevier B.V. All rights reserved.