Effect of TiO2/SiO2 molar ratio on the structure, dielectric and crystallization properties of SiO2-TiO2-ZrO2-RO-Al2O3 glasses

Understanding the role of TiO2 in glass structure is the key to the development of new functional glass materials. In this work, the changes in the structural units of SiO2-TiO2-ZrO2-RO-Al2O3 (R=Ca, Sr, Ba) multicomponent glass were characterized by X-ray photoelectron spectroscopy, magic angular spinning nuclear magnetic resonance and Raman spectra. It is determined that with increasing TiO2/SiO2 molar ratio, the amount of [TiO4] and [TiO6] increase at the expense of [TiO5] and the coordination of Al3+ changes little. Si4+is mainly linked in the Q3 and its proportion is related to the change of TiO2 content, which infers that the nonbridging oxygen number, the proportion of Si-O-Ti, Ti-O-Ti and Si-O-Si also varies accordingly. The changes in structure also affect the performance of the glass. The results indicate that the substitution of TiO2 increases the density and dielectric constant of the glass, makes the glass thermal stability decrease slightly. This work provides a basis for the performance tailoring of high dielectric glass fiber.