Acrylates, for example ethyl or isooctyl .alpha.-cyano-.beta.,.beta.-diphenylacrylate, methyl .alpha.-carbomethyoxycinnamate, methyl or butyl .alpha.-cyano-.beta.-methyl-p-methoxycinnamate, methyl .alpha.-carbomethoxy-p-methoxy cinnamateand N-(.beta.-carbomethoxy-.beta.-cyanovinyl)-2-methylindoline.2.5.