[en] Amorphous silica materials have been successfully prepared by the controlled hydrolysis of tetraethoxysilane and glycidyloxypropyltrimethoxysilane. The rhodamine B has been introduced into the hydrolized silicate solutions. Thin films have been obtained by spin-coating of the obtained hydrolizates on quartz glass substrates. The morphology of the resulting thin-film samples have been characterized by optical and atomic force microscopies. The spectroscopic properties of samples have been characterized by FT IR and UV-VIS-NIR absorption measurements. The photoluminescence spectra have been recorded at room temperature. The emission of the hybrid materials doped with the dye exposed to UV radiation as a function of laser pulses has been measured. Basic physicochemical properties of the modified silica materials have also been determined

[en] The main objective of this paper is to focus on the use of new techniques to specifically characterize BaTiO₃ nonlinear nano-crystals as a test case. We use the second harmonic generation (SHG) of an IR YAG:Nd pump laser and detection of the Yb³⁺ ion pairs to investigate effect of doping and synthesis route (sol-gel between 700 and 1200 deg. C) on both crystallite sizes (25-60 nm) and different phase symmetries (tetragonal, cubic, hexagonal) in Yb³⁺-doped BaTiO₃. In nano-crystals, a higher intensity of SHG was observed in the acentric tetragonal phase, whereas the isotropic cubic phase was detected by the absence of a SHG signal. Cooperative emission, indicating the presence of Yb³⁺ ion pairs, was easily detected in the cubic phase and not seen in the ferroelectric tetragonal structure