One. Scientific Foundations of Hollow Glass Microspheres one.one Composition and Microstructure 1.1.one Chemical Composition: Borosilicate Dominance Hollow glass microspheres (HGMs) are largely made up of borosilicate glass, a fabric renowned for its low thermal growth coefficient and chemical inertness. The chemical make-up usually features silica (SiO₂, 50-90%), alumina (Al₂O₃, ten-... http://www.mysportsgo.com/profile/okok0972/action_id/1516636/show_comments/1