Lithium niobate bulk crystallization promoted by CO2 laser radiation

The crystallization induced by laser radiation is a very promising technique to promote glass/ceramic transformation, being already used to produce crystalline patterns on glass surfaces. In this work, a SiO2–Li2O–Nb2O5 glass, prepared by the sol–gel route, was submitted to CO2 laser radiation and conventional heat-treatments in order to induce the LiNbO3 crystallization. The structure and morphology of the samples prepared by both routes was analyzed as a function of exposure time, radiation power and heat-treatment temperatures by XRD, Raman spectroscopy and SEM. The results reveal a correlation between the crystallization degree of LiNbO3 particles and glass matrix with the heat treatment type and experimental parameters. An heat-treatment at 650 °C/4 h was necessary to induce crystallization in heat treatments samples while 4 W/500 s was enough for laser radiation ones, corresponding a reduction time processing of ∼14 000 s.