Three component PbO–Bi2O3–Ga2O3 glasses are characterized by high midIR transmittance, with a large susceptibility to crystallization. In this paper we investigate the increase in the thermal stability of these glasses by the addition of oxides such as GeO2, SiO2, Tl2O, CdO, Nb2O5. The resulting multicomponent glasses are well suited for the fabrication of microstructured fibers and micro-optical elements. The increased thermal stability of the modified multi-component glasses resulted in the IR absorption cut-off shifting to shorter wavelengths.