Study On Crystallization And Second Order Non-linear Optical Properties Of SrO-TiO₂-SiO₂ Glasses

Non-linear optical Materials are very important for the information age. Glasses as non-linear materials have attracted much attention due to their many advantages. Especially polar crystallized glasses, which can be oriented by some directional crystallization processes, have good piezoelectric, pyroelectric and non-linear optical properties.In this paper, we have synthesized SrO-TiO2-SiO2 glass by melt-quenching method, emphatically discussed the influence of different thermal treatment conditions on second harmonic generation (SHG), and the polar oriented crystallization mechanism.According to the SrO-TiO2-SiO2 phase diagram, the reasonable base glass composition is SiO2:TiO2:SrO=2.9:1:2.When 2.0SrO-1.0TiO2-2.9SiO2 base glass heating at 850℃for 2 hours, surface crystalline phase Sr2TiSi2O8 preferred orientating in the polar direction [002]. Particle size is about 200-500nm, crystalline layer is about 15μm.The transmittance of these samples decreased quickly with increasing the heat treatment temperature and hours, with the absorption edge around 350nm.The SHG was observed when the heating temperature was over 850℃for more than 2 hours. The maximum second harmonic (SH) intensity of SrO-TiO2-SiO2 glass is about 2.5 times larger than that of a-quartz. With the increasing of heat treatment temperature and hours, the SH intensity increased slowly, but the Maker fringe patterns began to become broader, which was similar to the bulk crystallization glasses.The SH intensity increased about 25%, with 3kv at 850℃for 3 hours. Maker fringe patterns show the characteristic of bulk crystallization glasses.