Laser induced modification on 40BaO–45B2O3–15TiO2 glass composition

This paper describes a study concerning the permanent modification of 40BaO–45B2O3–15TiO2 (mol%) glass composition when irradiated by a continuous CO2 laser beam. Three parameters of the permanent modification and crystallization processes induced by irradiation were studied: laser power, irradiation time and the presence of micrograins of β-BaB2O4 (β-BBO) crystalline phase on the glass sample surface prior to irradiation. The geometry of permanent deformation induced by irradiation depended mainly on the laser power and sample surface condition. Crystallization of the irradiated region was observed when laser power at around 0.72 W and an irradiation time of around 300 s were used. The structural characterization performed by micro-Raman and X-ray diffraction techniques showed the formation of only the BaTi(BO3)2 crystalline phase on the as-polished sample. On the other hand, when β-BBO microcrystals were homogeneously dispersed onto the glass surface, the formation of the β-BBO phase was induced. In this condition, the β-BBO becomes the main crystalline phase and presents a certain degree of texture.