Physical, structural and opto-mechanical modifications in novel B2O3-CaO-ZnO-BaO-Dy2O3 glasses via BaO doping: Implications for gamma-ray shielding applications
M.I. Sayyed, Shrikant Biradar, K.A. Mahmoud
Abstract
In this investigation, a series of B 2 O 3 -based glasses with the formulation (78-y)B 2 O 3 –7CaO-14ZnO-yBaO-1Dy 2 O 3 ( y = 27, 30, 33 and 36 mol%) were synthesized via conventional melt-quenching to examine the influence of BaO on structural, mechanical, optical, and radiation shielding capabilities. Increasing BaO content altered the structure by replacing lighter B 2 O 3 with heavier BaO, raising density (4.103 to 4.407 g/cm 3 ) and reducing network connectivity, as shown by higher Ba ion concentration and shorter inter-ionic distances. Mechanically, the glasses exhibited reduced elastic moduli with increasing BaO content, as the bulk modulus decreased from 74.416 to 63.701 GPa and the shear modulus from 34.562 to 31.236 GPa, suggesting decreased rigidity. FTIR and UV–Visible absorption analyses revealed the formation of increased non-bridging oxygen sites, and redshift in the optical edge, indicating rising structural disorder. Consequently, the optical bandgap decreased (3.096 eV to 2.991 eV for direct and 2.865 to 2.698 eV for indirect transitions), while Urbach energy (0.176 to 0.224 eV) and refractive index (2.434 to 2.483) increased, revealing a shift toward a more polarizable and disordered network. Importantly, the radiation shielding efficiency improved with BaO enrichment due to increased density. The simulation and theoretical data showed good agreement, with a discrepancy of only ±1.5 %. The effective atomic number increased from 42.97 to 45.56, and the linear attenuation coefficient at 0.05 MeV rose from 24.06 to 30.97 cm -1 . The half-value layer at 15 MeV decreased from 5.42 to 4.69 cm, confirming better γ-ray attenuation with higher BaO content. These results show that the glasses, especially those with higher BaO (BCaD4), offer strong potential as gamma-ray shields while preserving optical clarity, mechanical strength, and structural integrity.