Silicium gels doped with cobalt(II) are prepared by a sol-gel process. Starting materials, Si(OCH3)4 and COCl2.6H2O, are dissolved in CH3OH in presence of HCL. Influence of several parameters on the transparency, monolithicity and color of gels is studied. Drying gels at room temperature leads to various colored glasses. I.R. studies show that Co(II) ions are not engaged in the Si-O-Si network, but keep outside this network in complexed forms with water molecules and chloride ions. This result is in agreement with the migration experiment 95% of Co(II) ions are left off the prepared materials when these are brought in contact with water or methanol.
F. Touati, N. Gharbi