Multilayer systems of thin silver films and dielectric layers are used for example in low-e windows. The optical properties of the silver films differ markedly from the optical properties of bulk silver and are influenced by the deposition of the top dielectric layer. Recently, we presented a dual-ion-beam sputtering apparatus with in-situ monitoring of reflectance and dc- resistance. The dielectic, Si3N4, was produced by sputtering silicon and assisting with an energetic nitrogen beam (200 eV). A sharp reduction in reflectance and a corresponding increase in dc-resistance of the silver film was observed during the first stage of the deposition. It was speculated that a thickness reduction of the silver film due to sputtering by the energetic nitrogen ions might cause some of the changes. In the present paper, we report measurements of film thicknesses by grazing incidence x-ray reflectometry (GIXR), which allow to exclude thickness reduction. We show that the optical absorptance of the sandwich system increases during deposition of the top dielectric layer. Different elements (Al, Si, Ta, and Ti) were sputtered onto the silver film without assisting, causing similar changes as dual- ion-beam sputtered Si3N4. Furthermore, Si3N4 was sputtered directly from a dielectric target. In contrast to the other materials, we observed only small changes in reflectance and dc-resistance.