Abstract: A hardener for epoxy resins includes at least one amine of the formula (I) and an amine-functional adduct of at least one polyoxyalkylene polyamine and a diepoxide. The hardener enables transparent epoxy resin compositions of high clarity, which are free of toxic diluents such as nonylphenol, upon curing show a low heat generation but still cure fast and reliably and have a high robustness against yellowing. Such epoxy resin compositions are particularly suitable as casting resin for the manufacturing of transparent articles with a glass-like appearance.