Spectral properties and dynamics of luminescent states of Pr3+ and Tm3+ in lead borate glasses modified by PbF2

A heavy metal oxide borate glass with composition (70−x)PbO–18B2O3–6Al2O3–3WO3 (wt%) was modified by variable content of PbF2 (image, 36 and 72 wt%) and doped with 1 wt% of Pr3+ or Tm3+ ions. The influence of the PbF2 content on optical properties and luminescence dynamics has been observed through the variation of an effective line width of 1D2→ 3H4 and 1G4→ 3F4 emissions as well as the 1D2 and 1G4 lifetimes of Pr3+ and Tm3+, respectively. It was observed that the increase of PbF2 content leads to narrowing of the 1D2→3H4 band from 680 to 590 cm−1. This effect was not observed for the 1G4→3F4 thulium emission.