Advancing multifunctional materials for environmental and technological applications requires the design of systems that combine structural stability with enhanced optical, photocatalytic, and dielectric properties. In this context, phosphate-based glasses and glass-ceramics within the ZnO–Na₂O–P₂O₅–TiO₂ system were investigated, with particular emphasis on the role of TiO₂ incorporation. Controlled thermal treatments were employed to induce partial devitrification, yielding crystalline phases finely dispersed within a residual glassy matrix. Structural and microstructural characterizations confirmed the amorphous nature of the as-prepared samples and their progressive crystallization upon heating, highlighting the contribution of Ti–O–P linkages to network reinforcement.

Optical analyses demonstrated a noticeable enhancement in UV absorption and a red shift of the absorption edge with increasing TiO₂ content, coupled with a slight narrowing of the optical band gap. These modifications indicate improved light-harvesting efficiency, which is beneficial for photocatalytic applications. Photocatalytic activity was evaluated through the degradation of methylene blue under UV–visible irradiation. All studied compositions exhibited photocatalytic effects, with higher TiO₂ concentrations accelerating the degradation process, thus confirming the catalytic role of titanium.

Dielectric investigations revealed frequency-dependent permittivity, with significant improvements observed upon TiO₂ addition. The reduction of polarization losses and stabilization of dielectric behavior further emphasized the potential of these materials for electronic and energy-related uses.

Overall, these results demonstrate that TiO₂-doped phosphate glasses and glass-ceramics successfully integrate optical, photocatalytic, and dielectric functionalities, making them promising candidates for advanced applications in environmental remediation and dielectric technologies.