Sol-gel and colloidal glass processing

Sol-gel glass processing gained scientific and technological importance in 1970, generating a new approach to preparing ceramics and homogenous glasses at low temperatures. Since then, sol-gel technology has continued to progress with an improvement of existing functional materials and the exploration of novel materials to be utilized in many research areas such as electronics, chemistry, mechanics, pharmacy, and medicine. The overall structure and properties of glasses synthesized by sol-gel technology are similar to those of melt-formed glasses that are obtained by using traditional processing methods. However, due to the high cost of raw materials and long processing time with very fine-tuned processing requirements for sol-gel approaches, they are not typically used in the large-scale commercial production of ordinary silicate glass pieces. This chapter will describe the theory and chemistry of sol-gel processes, the routes to utilize this process to make 3D objects, and the relevance of such processes to the field of 3D printing of glass.