Er3+ doped thin glass films were produced by the sol-gel technique. The best active properties were obtained for GeO2-SiO2 matrices codoped with P2O5 or Al2O3. We succeeded in limiting the influence of OH groups on the active properties by special heat treatments. Narrow fluorescence spectra (similar to 20 nm) and long lifetimes (similar to 6 ms) were found in P2O5 co-doped samples whereas Al2O3 co-doping gave wider spectra (similar to 50 nm) with slightly lower lifetimes (similar to 5 ms). The quenching concentration in the Al2O3 co-doped samples was 0.9% Er3+.