Stimulated surface crystallization of beta-barium borate on glass due to ultrasonic treatment and second harmonic generation

A glass of 47.5BaO . 47.5B(2)O(3) . 5Al(2)O(3) (in mel %) having a shorter optical absorption edge (similar to 236 nm) and suitable glass formation was selected as the mother glass for studying the surface crystallization of beta-BaB2O4. beta-BaB2O4 was not the main surface crystallized phase when only a conventional heat treatment was applied. Crystallization of beta-BaB2O4 was stimulated due to ultrasonic surface treatment with an ethanol suspension of beta-BaB2O4 particles and subsequent heat treatment. After the ultrasonic treatment, beta-BaB2O4 was the main crystallized phase. Transparent and dense beta-BaB2O4 thin films/glass showed second harmonic generation, The tensor components of the second-order nonlinear optical susceptibility were estimated.