Optical and dielectric features of zinc oxy fluoro borate glass ceramics with TiO2 as crystallizing agent

ZnO–ZnF2–B2O3 glasses were synthesized and crystallized with different concentrations of TiO2 (0–0.5 mol% in the steps of 0.1) as nucleating agents. The prepared samples were characterized by XRD, SEM and DSC. These studies have revealed that the samples contain well defined randomly distributed crystalline phases with the complexes of Ti4+ and Ti3+ ions. Optical absorption studies have indicated that a part of titanium ions exist in Ti3+ state in the bulk samples. Dielectric properties were also studied over broad ranges of temperature and frequency of the glass ceramics. The obtained results were analyzed in terms of different polarization mechanisms. The dielectric break down strength of titled glass ceramics was also measured at room temperature in the air medium. The break down strength is found to decrease with the concentration of nucleating agent. The analysis of the results of dielectric properties indicated a decrease of insulating strength of the glass ceramic samples with increase of TiO2 content.