Effects of Doping Trivalent Ions in Bismuth Borate Glasses

Bismuth borate glasses from the system: 40Bi(2)O(3)-59B(2)O(3)-1Tv(2)O(3) (where Tv = Al, Y, Nd, Sm, and Eu) and three glasses of composition: 40Bi(2)O(3)-60B(2)O(3), 37.5Bi(2)O(3)-62.5B(2)O(3) and 38Bi(2)O(3)-60B(2)O(3)-2Al(2)O(3) were prepared by melt quenching and characterized by density, UV-visible absorption spectroscopy and differential thermal analysis (DTA) studies. Bismuth borate glasses exhibit a very strong optical absorption band just below their absorption edge. Glasses were devitrified by heat treatment at temperatures above their glass transition temperatures and the crystalline phases produced in them were characterized by Fourier transform infrared (FTIR) absorption spectroscopy and X-ray diffraction (XRD). Bi3B5O12 was found to be the most abundant phase in all devitrified samples. DTA studies on glasses and FTIR and XRD analysis on crystallized samples revealed that very small amounts of trivalent ion doping causes significant changes in the devitrification properties of bismuth borate glasses; rare-earth ions promote the formation of metastable BiBO3-I and BiBO3-II phases during glass crystallization.