Compositions including a combination of (meth)acryloyl-terminated monomers and oligomers prepared by co-reacting reactants having active hydrogen groups with an acrylating agent are disclosed. Polymerizates formed using the combinations of (meth)acryloyl-terminated monomers and oligomers exhibit a high hardness, excellent thermomechanical properties, and a high refractive index. The compositions can be used to fabricate optical components.