Sunlight is essential for life on earth. Many biological processes are influenced by the light of the sun and humans also react sensitively to it. Therefore, this light and its incidence have a decisive influence on the comfort inside buildings. Hence, glass, as a transparent building material, is an elementary design element in modern architecture. To support the clear appearance, transparent adhesives represent an attractive alternative to opaque adhesives as well as to opaque structural sealants. But solar radiation affects such adhesives or sealants negatively through the absorption of UV-light that leads to unfavorable changes in material properties and has a significant effect on their durability. To estimate the service life of structural adhesive joints in glass constructions a large number of accelerated aging processes are carried out on a laboratory scale. In the case of UV aging, the accelerating effect is mainly achieved by continuously irradiating the samples. The radiation flux is mostly constant what only partially represent real solar radiation effects. A precise knowledge of the real light impact on the building envelope is needed to be able to evaluate the received material stresses after artificial aging correctly.

In this study, transparent adhesives are conducted to standardized, time-shortened sunlight aging methods followed by the examination of the effects via spectroscopic and chemical analysis. These results are evaluated with regard to real amounts of radiation occurring on a building. Corresponding data are used from a simulation of the solar radiation exposure depending on season and weather influences as well as on the location and orientation of the building. The aim is to identify zones with such high radiation amounts which cause damage of the adhesives and to investigate and recommend constructive protective measures.