Eu2+ ions were incorporated in SiO2 and Al2O3–SiO2 glasses using a sol‐gel process of Si(OC2H5)4, Al(OC4H9sec)3, and EuCl3 6H2O. Glasses incorporated with the Eu2+ ions showed the emission with peak at ∼22000 cm−1 due to 4f6 5d→4f7(8S7/2) transition of the Eu2+ ions. 1Al2O3⋅99SiO2 (mol %) glass had an intense emission, 250 times larger than that of 100SiO2 glass. 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 4f6 5d level to be small, resulting in an increase in the probability of the radiative relaxation from the 4f6 5d to 4f7(8S7/2) level.