X-ray absorption spectroscopy makes it possible to identify the local atomic structure around cations in ion-exchanged glasses. EXAFS experiments demonstrate that the substitution of sodium by silver leads to local rearrangements below TG. In contrary to that the incorporation of ions with increased ionic radii as K or Rb leads to a simple replacement of cations at low temperatures. Increasing the exchange temperature, the introduced cations form their own environment that is, however, determined by the soda-lime glass network. The structural parameters of nanoscale silver particles embedded in a silicate glass matrix have been determined by temperature-dependent EXAFS spectroscopy at the Ag K edge for particles between 2.5 and 6 nm. The lattice parameter of the Ag particles showed an unusual dilatation of the silver structure that is a result of the glass cooling process. Furthermore, an increase was found of the Debye-Waller factors as well as of the thermal expansion coefficient compared with bulk Ag material. The experiments demonstrate that the behaviour of metal particles incorporated into a glass matrix reflects the influence of the surrounding matrix. |