Stereolithography is a 3D printing technology for converting liquid photo curable resin into 3D dimensional shaped objects. The choice of commercial resins is nowadays very limited, and a lot of work is done worldwide to study innovative formulations with improved properties and different functionalities. In the present work hollow glass micro spheres were added to photo curable resins to increase the mechanical properties of the cured system without affecting the final material density. The photo curable suspensions were optimized ignorer to obtain a good stability during the printing process. The obtained 3D printed objects were fully characterized by SEM analysis, thermal and thermo mechanical analysis as a function of different sphere content.