| abstract |
The invention relates to transparent, photochromic or nonphotochromic organic materials, which have a refractive index higher than 1.55 and which are free of optical distortions, consisting of a copolymer of:(a) 50-90 wt. % of at least one monomer represented by the formula,in which R=H or CH3, and m and n are independently 1 or 2;(b) 10-30 wt. % of at least one aromatic monovinyl monomer represented by formula,R1=H or CH3; and(c) 1-20 wt. % of at least one (meth)acrylic monomer represented by formula,in which R=H or CH3R' is a straight-chain or branched C4 to C16 alkyl radical, an alkylaryl radical, or a polyoxyethoxylated group with formula -(CH2-CH2O)nR'' in which n=1 to 10 and R''=CH3 or C2H5. Optionally, the photochromic material may contain up to 10 wt. % of at least one photochromic coloring agent to impart desired photochromic properties.The material which may also contain up to 15 wt. % of an aromatic divinyl monomer represented by the formulawhere R1=H or CH3., may be polymerized in the presence of up to 0.5 wt. % of at least one non-peroxide radical polymerization initiator.The organic material is particularly useful for the production of ophthalmic lenses and glazings for such objects as vehicles and buildings |