Study Of The Refractive Index Of Microscopic Glass Beads By Light-Refraction Analysis

The refractive index of submillimeter glass beads has been measured by means of a procedure with reference liquids that does not require close index matching and therefore avoids the use of toxic compounds for high-index glasses. The method is based on the analysis of the light refracted by a monolayer of beads in comparison with ray-tracing simulations. For the three types of beads investigated, a satisfactory fit is achieved by the assumption of a radial variation of the refractive index inside the beads. This is ascribed to the tensile and compressive stresses originating inside the beads during rapid solidification of the glass.