This study examines the optical properties of (45-x) B2O3-6PbO-18ZnO-31Bi2O3–xEu2O3 glasses (x = 1, 2, 3, and 4 mol%), synthesized using the melt-quenching method. UV-Visible spectra exhibit characteristic absorption peaks of Eu2O3, with intensities increasing proportionally to the Eu2O3 content. Optical analysis reveals a decrease in the direct energy band gap (Eg) from 2.906 eV to 2.623 eV in the Eu1 to Eu2 samples, attributed to an increase in non-bridging oxygens (NBOs). Conversely, an increase in Eg values from 2.795 eV to 2.842 eV in the Eu3 to Eu4 samples suggests structural densification. The Urbach energy (EU) increases from 0.176 eV to 0.520 eV in the Eu1 to Eu2 samples, while it decreases from 0.222 eV to 0.165 eV in the Eu3 to Eu4 samples. Trends in the refractive index reflect the influence of non-bridging oxygens (NBOs) and bridging oxygen (BO) ratios on the glass network. The dielectric constant (ε), molar refractivity (RMolar), and polarizability (αMolar) correlate with variations in Eu2O3 content. A reduction in metallization values from 0.370 to 0.319 indicates increased metallicity from Eu1 to Eu2, while an increase in metallization values from 0.358 to 0.365 for Eu3 and Eu4 suggests a shift toward a more non-metallic nature, consistent with the observed bandgap widening. These findings underscore the intricate relationship between glass structure and optical behavior, paving the way for potential applications in optoelectronic materials