1. CERTEV — Center for Research
2. Technology and Education in Vitreous Materials
3. Department of Materials Engineering
4. Federal University of São Carlos
5. São Carlos
6. Institut für Physik
7. Universität Rostock
8. 18051 Rostock
9. Germany
10. Departament of Science
11. State University of Maringá
12. 87360-000 Goioerê
13. Brazil