SOL-GEL PROCESS FOR PRODUCING A DRIED GEL ADHERING TO AN INSERT AND PRODUCTS OBTAINABLE THEREBY

摘要

A sol-gel process is described that allows dry gels to be produced, and wher e necessary, the corresponding dense vitreous bodies, around an incompressible insert. A particular feature of the process is the step of rotating a container holding the sol and incompressible insert throughout the gelling step under such conditions that a wet gel adhering to the insert is produced , which is then dried. The process is useful particularly for the production o f preforms for optical fibers, which are also claimed.