GLASS MICROSPHERES OF HIGH REFRACTIVE INDEX

摘要

Glass microspheres having an index of refraction of 2.7 or higher are prepared by (1) forming the microspheres from compositions based principally on 65-85 weight-percent Bi2O3 and 5-35 weight-percent TiO2, and (2) rapidly heating the microspheres after they have been initially formed to cause an internal structural rearrangement that raises their index. Such microspheres are useful to form retroreflective products having superior properties and a more simplified construction.