NONLINEAR GLASSES BY METAL CLUSTER FORMATION - SYNTHESIS AND PROPERTIES

Light waveguides were obtained by Na+ reversible arrow Ag+ ion-exchang e in a commercial soda-lime glass of composition (wt%): 71.9 SiO2, 1.9 Al2O3, 6.8 CaO, 1.1 K2O, 4.4 MgO, 13.5 Na2O, 0.4 SO3, with small cont aminations of iron (15 ppm) and arsenic (300 ppm). Glass samples were immersed for 30 min in a molten salt bath of molar concentration 0.1% AgNO3 in NaNO3 at 320 degrees C. Ion-exchanged samples were irradiated with helium, lithium and neon ions at an energy of 100 keV, with flue nces in the 1x10(16)-1x10(17) ions/cm(2) range and current densities b etween 1 and 8 mu A/cm(2). The effect of the substrate temperature (ro om temperature, 90, 150 and 250 degrees C) was investigated. The forma tion of nanometer-size silver precipitates was observed, after irradia tion, depending on the treatment conditions. ?he results were interpre ted on the basis of the diffusivity of silver at the different tempera tures and of the values of the energy deposited by the ion beams in el ectronic (ionization) processes and elastic collisions. Preliminary me asurements of the third-order contribution to the electrical susceptib ility indicate that the obtained materials exhibit optical non-linear properties which are interesting for the fabrication of optoelectronic devices.