A Study on Gradient Refractive Index Polymer Rods——Mechanism of Diffusion-Copolymerization of Diallyl Phthalate-Methyl Methacrylate

The gel rod, partially polymerized DAP (diallyl phthalate), is immersed in MMA (methyl methacrylate) solution, followed by heat-treatment to yield the GRIN (gradient ref- ractive index) rod. A three-stage mechanism of diffusion-copolymerization process is propo- sed, giving an interpretation to the formation of cracks that are brought about in large-dia- meter GRIN rods.