Abstract
We present results from dielectric spectroscopy on four molecular glass-formers, both in bulk and in confined geometry. For systems exhibiting a well-resolved secondary (β) relaxation, the confinement induces a relative enhancement (compared to the main α relaxation) of the effective dielectric strength of the β process. In bulk systems without a well-separated β process a similar relative enhancement is found also for the contribution to the dielectric loss identified as the excess wing. The latter effect results in a bimodal loss, which suggests that the excess wing should be attributed to a relaxation process separate from, and thus not a feature of, the α relaxation. The results hence provide an explanation for the much debated excess wing often observed in the dielectric response of glass-formers.