Laser-induced crystallization in vanadate glasses

Supervisor
Mario Affatigato - Coe College, Iowa, visiting professor at Physics Dep of Trento
Date and time
Thursday, April 24, 2008 at 10:30 AM
Place
Ca' Vignal - Piramide, Floor 0, Hall Verde
Programme Director
Gino Mariotto
External reference
Publication date
April 18, 2008
Department
 

Summary

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.






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