Eu2+ions were incorporated in SiO2and Al2O3–SiO2glasses using a sol‐gel process of Si(OC2H5)4, Al(OC4H9sec)3, and EuCl36H2O. Glasses incorporated with the Eu2+ions showed the emission with peak at ∼22000 cm−1due to 4f 6 5d→4f 7(8S7/2) transition of the Eu2+ions. 1Al2O3⋅99SiO2(mol %) glass had an intense emission, 250 times larger than that of 100SiO2glass. The covalency of the Eu–O bonds is decreased by the Al3+ions. We concluded that this weak covalency causes the offset of the excited 4f 6 5dlevel to be small, resulting in an increase in the probability of the radiative relaxation from the 4f 6 5dto 4f 7(8S7/2) level. ©1996 American Institute of Physics.