A process of poling a silica material such as an optical fiber whereby electro-optic non-linearities are induced so that the material can function as a phase modulator and switch in optical communications applications. The poling is effected at an elevated temperature on the order of 450° C. or higher, using an electric field on the order of 800 V/&mgr;m or higher for a period of time in the range of one minute to several tens of minutes.