Thermal, optical and spectroscopic properties of fluorogallate PZG (PbF2–ZnF2–GaF3) and fluoro-gallo-indate PIG (PbF2–InF3–GaF3) glasses doped with PrCl3 and PrF3 have been investigated. Absorption and luminescence properties of these glasses have been studied in the visible and in the second telecom window around 1.3 μm. Fluorescence lifetimes of the 1G4 level have been compared between praseodymium chloride and fluoride doped glasses. Longer decay constants have been obtained for PrCl3 doping at low concentration (0.05 mol%). This effect has been related to a reduction of both the phonon energy in the surrounding of the rare earth ion and the electron–phonon coupling, leading to a decrease of the non-radiative multiphonon relaxation rate.