Design of zero-birefringence cross-linked polymers

We analyzed thermoplastic methacrylate polymers and found that their birefringence during polymerization is due to both orientational and photoelastic birefringence. We designed zero-birefringence cross-linked polymers that do not exhibit birefringence during the polymerization process or elastic deformation, and deduced the contributions of cross-linking agents to photoelastic coefficient by analyzing binary cross-linked polymers. When photoelastic coefficient values of ternary cross-linked polymers were almost zero, their average in-plane birefringence was linearly related with the concentration of cross-linking agents. Finally, we designed and demonstrated two types of zero-birefringence cross-linked polymers.