Characterization of heterophase inclusions in glasses opaque in the visible range

We have designed an apparatus and developed a nondestructive laser ultramicroscopy technique involving digital detection of the 0.98-mu m radiation scattered by individual inclusions for determining the concentration and size of submicron heterophase inclusions in high-purity glasses opaque in the visible range. The capabilities of the technique have been illustrated by analyzing several test systems. The detection limit for the inclusion size is shown to be n x (10-100) nm, depending on the refractive indices n of the inclusions and glass. The working range of inclusion concentrations is 10(2) to 10(9) cm(-3), and the maximum scan depth is similar to 1 cm. The technique has been used to assess the microinhomogeneity of selenium and As-S-Se glass samples.