Physical, structural, and radiation shielding properties of B2O3-MgO-K2O-Sm2O3 glass network modified with TeO2

A new series of Sm3+ doped Telluroborate glasses with varying TeO2 content have been prepared following the melt quenching technique. The physical properties like density, refractive index, average molecular weight, molar volume, optical dielectric constant, and metallization criterion were calculated. Structural properties like boron-boron separation (< d(B-B) >), molar volume of oxygen (V-o), oxygen packing density (OPD), average coordination number (m), bond density (nb), Poisson ratio (mu(cal)), optical electronegativity (chi(opt)), basicity (Lambda th), two photon absorption (TPA) coefficient (beta), ionic character (I-c), and covalent character (C-c) were calculated. In addition to that, optical bandgap and urbach energy (Delta E) values of the titled glasses have been calculated from Tauc's plot using the absorption spectra. It is observed that boron-boron separation (< d(B-B) >) and OPD increases with the decrease in molar volume of oxygen (V-o). Also, the increasing density and refractive index values with the progressive decrease of molar volume with increasing TeO2 content implies the formation of bridging oxygen (BO) along with nonbridging oxygen (NBO), which is later proved by the Poisson ratio values and basicity values. Further, ionic nature of the Sm3+ doped telluroborate glasses are identified from the measured optical basicity (Lambda th), covalent, and ionic characteristic factors. The observed variations in the optical electronegativity, basicity, metallization criterion, and optical bandgap energy (E-g) values have been discussed in terms of the structural changes that take place due to the addition of TeO2 into the B2O3 network. The gamma photon shielding properties for the prepared samples were studied using MCNPX code in the energy range of 0.356-1.33 MeV. The obtained mass attenuation coefficient exhibit an increasing trend as the TeO2 content vary from 0 to 40 mol%, especially at the energy 0.356 MeV. Of all the glasses, 4TBS glass sample shows lowest halfvalue layer value. The study confirms that the replacement of B2O3 by TeO2 enhances the capability of the prepared glass samples to reduce the gamma photons.