Molecular Gradation In Glass By Using High Gravity: A Novel Method For Si-Ti Graded-Glass Preparation

We investigated the preparation of functional graded glass by using the sedimentation of colloid particles under a high gravity field in combination with a sol-gel method. The precursor gel of the graded glass was prepared by centrifuging Si and Ti sols during the conversion from sol to gel. The SiO2 - TiO2 graded glass was obtained by heating the gel. The optimal conditions for the preparation of the graded glass were determined by changing the times of three steps: homopolymerization, mixing and copolymerization. By lengthening the homopolymerization time and centrifuging quickly after mixing Si and Ti sols, SiO2 - TiO2 system graded glass could be obtained. The resulting glass had a graded structure at the molecular scale. Efforts are necessary to prevent cracks. We will prepare graded glass containing transition elements and rare earth elements. These are expected to show useful optical properties.