Sol–gel processing of optical and electrooptical materials

The sol–gel process represents a room‐temperature method of producing a wide range of ceramic materials through the formation of a glassy network by the polymerization of suitable monomers. The use of the technique to produce, for example, sonogels, organic‐inorganic composites, NLO glasses, and electrooptical materials such as gel‐glass dispersed liquid crystald (GDLCs) is reviewed. An example of a GDLC is shown on this issue's front cover, 4‐pentyl‐4‐biphenylcarbonitrile in the LC state being dispersed in a thin film of silica.