The composition, structure and strength of titanium doped hollow glass microspheres (HGMs) were studied. Results showed that the strengths of titanium doped glass spheres were determined by the composition, structure and geometric qualities of glass shells. The Young's modulus of HGMs reduced with the increasing titanium concentrations due to the decreased geometric quality of shells and increased with the increase of the fabrication temperature because of the greater loss of alkali oxides at higher temperature. Even though the calculation on the falling process showed that class B HGM had longer average residence time in furnace than class A HGM and consequently greater loss of alkali oxides in glass, the strength of class B HGM was reduced as a result of the generations of oxygen vacancy and phase separation. The strength of class B HGM was improved by compensating oxygen atom by heat treatment in air.
