Compositional dependence of transparency, linear and non-linear optical parameters, and radiation shielding properties in lanthanum, iron and calcium borate glasses

In this paper, we synthesized a novel lanthanum, iron, and calcium borate glasses system by changing lanthanum oxide (La2O3)/boron oxide (B2O3) contents and investigated their structure, optical parameters, and radiation shielding characteristics. Optical absorbance and transmittance were measured, while the optical band gap values were obtained by investigating the fundamental absorption edges via Tauc's plot. Our analyses show that all glass samples show good transparency in the visible range; further, the transparency increases from 64% to 72.5% (at 600 nm) with increasing La2O3/B2O3 contents. Moreover, with increasing La2O3/B2O3 contents, the fourfold coordinated boron units (BO4) increase, the density increases, and the trigonal boron units (BO3) decrease. Furthermore, with increasing La2O3/B2O3 contents, the fundamental absorption edges shift toward higher wavelengths, and the optical band gaps decrease. Also, with increasing La2O3/B2O3 contents, the linear and non-linear refractive indices increase. These behaviors were justified by the decreased electronegativity and increased electronic polarizability values. On the other hand, the radiation shielding properties, such as the mass attenuation coefficient and half value layer, show enhanced behaviors with further La2O3 additions. The com-bination of enhanced radiation shielding properties and enhanced transparency makes the current glasses good candidates in the radiation shielding field.