To make it possible to form polarizable regions within nonpolarized glass by applying a protective material (frit barrier layer) on the surface of the glass to form the patterns of the regions to be protected and the regions not to be protected.

The glass surface including silver contg. phase separable silver halide particles is coated with a mixture composed of glass frit and photoresist. The coated glass is dried and is exposed with UV light through a mask including the desired polarized-nonpolarized glass patterns. The glass is developed and the frit material of the exposed parts or nonexposed parts is removed and thereafter, the glass is heated to sinter the remaining glass frit material. The glass is then subjected to a reducing gas treatment, by which the silver ions are reduced to an atomic state and are made polarizable. The sintered frit material is removed by, for example, acid etching to expose the underlying nonpolarizable glass. The glass obtd. in such a manner is identified by the patterns of the polarizable and nonpolarizable glass regions.