PbWO4 formation during controlled crystallization of lead borate glasses

Lead borate glasses were prepared and then heat treated in order to obtain transparent glass-ceramics. Controlled crystallization of precursor lead borate glass at appropriate annealing temperature and time led to formation of the PbWO4 crystallites. The observed broad blue emission band is related to the PbWO4 crystallites. The influence of PbX2 content (X=F, Cl, Br), PbF2 concentration and lanthanide doping (Eu, Dy) on the excitation and emission spectra of lead borate glass-ceramics containing PbWO4 phase was examined. The relationship between Pb-X bond and spectral line width of the blue emission can be successfully observed, when halogen X ions (X=F, Cl or Br) are also present in the distorted PbWO4 crystallites.