Surface crystallization of stoichiometric glass with Bi₂ZnB ₂O₇ crystal using ultrasonic Surface treatment followed by heat treatment

Surface crystallized glass-ceramics with nonlinear optical Bi ₂ZnB₂O₇ (BZB) crystals were prepared by ultrasonic surface treatment (UST) followed by crystallization heat treatment for stoichiometric glass with a composition of 33.3Bi₂O ₃-33.3ZnO33.3B₂O₃. According to the surface XRD measurements and microscopic observations, UST technique was found to be quite effective for lower temperature precipitation of BZB, indicating the ability of crystallization control of the target phase, such as phase selectivity, small size of precipitates, high orientation and their morphology. After the optimization of the process condition parameters for improving transparency and suppressing deformation of the sample, the effective optical nonlinearity of the transparent surface crystallized glass-ceramics was estimated as 0.7pm/V.