Preparation of silica glasses containing Eu2(CO3)3 4H2O by means of sol-gel technology was described. The absorption, emission, and excitation of Eu2(CO3)3 4H2O compounds in powder and entrapped in silica sol-gel glass were measured in a broad temperature range. It was found that the optical properties of europium ion direct environment were not preserved in silica glass. A broad band, in UV range, characteristic to Eu2+ ions or C-T transition, was also observed. The intensity of this broad band is controlled by temperature an concentration of the active ions. Following the energy diagram of f-f transitions derived from Eu2(CO3)3 H2O system, the symmetry of Eu3+ ion was discussed in precursor and gel spectra. The effect of anisotropy of europium ion was considered, too.
|