Obtaining transparent silica glass from nano-silica hydrosol

Transparent silica glass is widely used in various fields. However, a simple and economical method of synthesis remains to be developed for high-precision device manufacturing. In this study, transparent silica glass is fabricated from low-cost commercial nano-silica hydrosol. To obtain transparent glass, the crystallization temperature of bulk materials must be higher than their densification temperature. Based on XRD analysis, impurity ions such as Na+ have a strong influence on the crystallization characteristics of sintered samples. Purification can be performed by soaking preheated samples in boiling water for a given duration. Transparent silica glass was obtained for purified samples from acidic silica hydrosol sintered at 900-950 degrees C. The optical characteristics of the samples were investigated for the presence of silica glass, and the transparency was enhanced for samples sintered in vacuum. The mechanical and dielectric properties of the sintered samples were also characterized.