1. Scientific Foundations of Hollow Glass Microspheres one.one Composition and Microstructure one.1.one Chemical Composition: Borosilicate Dominance Hollow glass microspheres (HGMs) are mainly made up of borosilicate glass, a material renowned for its very low thermal expansion coefficient and chemical inertness. The chemical makeup typically features silica (SiO₂, 50-90%), alumina (A... http://www.mysportsgo.com/profile/okok0972/action_id/1516636/show_comments/1