The longer the wavelength, the smaller the deviation.
The refractive index
Apparently this ratio is smaller for longer wavelengths. I have not yet heard of a material in which this is the other way around.
The way the light is refracted differently from red to violet is a property of the material, and may differ greatly between one sort of glass and another. Some glasses have a low average refraction and a relatively great red-violet difference, with others it's the other way around. By combining lenses of these two glasses we are able to colour correct our photographic lenses.