Laser-induced crystallization in vanadate glasses

We report on our investigation of the effects of 785 nm light irradiation on lead and barium vanadate glasses. Whereas high powers (>84 mW) yielded crystallization and thermal modification of the surface, low powers (<38 mW) altered the sample without causing crystal formation. Scanning probe microscopy, scanning electron microscopy, EDX, and micro-Raman spectroscopy were used to characterize the changes induced by the laser light. As part of the work we made glasses in the range 10 < x < 60, where x is the molar percent of lead and/or barium oxide, as well as crystals corresponding to 2PbO.V2O5, 3PbO.V2O5, and 8PbO.V2O5. We also looked at the crystallization of other binary vanadate glass families. The healing of low-power damaged areas by annealing was studied, and we also made calorimetric measurements on the glasses. In general, the results point to a laser-assisted diffusion of lead and/or barium, which helps establish the right stoichiometric conditions for crystallization upon cooling from the laser irradiation. This research was supported by the National Science Foundation under grant DMR-CER-0502051, and by the Roy J. Carver Charitable Trust of Iowa.