A method comprising contacting at least one conventional elastomer, at least one singlet oxygen functionalized elastomer (SOFE), and a styrene monomer in a reaction zone under conditions suitable for the formation of a styrenic polymer composition. A method comprising contacting a reaction mixture comprising styrene, polybutadiene, and a photoperoxidized polybutadiene in a reaction zone under conditions suitable for the formation of a polymeric composition, wherein the elastomer particle size distribution in the polymeric composition does not linearly correlate with the elastomer particle size distribution in the reaction mixture. A reactor blended polymer comprising styrene, a conventional elastomer, and a singlet oxygen functionalized elastomer.