Synthesis of halide glasses by reactive processing of sol-gel materials

This paper aims to introduce fluoride materials, their conventional processing and how sol-gel processing can be used both to simplify processing and to improve properties. A multistep process incorporating sol-gel synthesis and reactive treatment is used to prepare a monolithic ZBLA fluoride glass. The first step is synthesis of a porous, monolithic, atomically homogeneous hydrous oxide gel containing zirconium, barium, lanthanum, aluminum and possibly sodium as components (ZBLA or ZBLAN). The second step is a relatively low-temperature reactive treatment of the gel with a fluorinating agent to achieve a porous fluoride glass. Subsequently, the gel is viscous sintered to a dense glass. The present status and future challenges in the preparation of optical-quality fluoride glasses via this method will be presented.