Design and synthesis of a zero-photoelastic birefringence polymer with a high glass-transition temperature by a random copolymerization method

We designed and synthesized a zero-photoelastic birefringence polymer that had a high glass-transition temperature (T_g) by introducing trans-stilbene units into the side chains of the copolymer by a random copolymerization method. The concentration of the trans-stilbene units required to compensate for photoelastic birefringence in the random copolymer was lower than that required in a polymer prepared by an anisotropic molecule dopant method, because the presence of an anisotropic moiety in the side chain of the polymer has a greater effect than an anisotropic molecule doped in the polymer. Furthermore, the polymer with trans-stilbene units in side chains showed a higher T_g than the polymer containing an anisotropic dopant. We conclude that the introduction of an anisotropic molecule of a similar or larger size to trans-stilbene into the side chain gives a polymer with a high T _g.