Photopolymer for anti-yellowing and anti-thermal cracking applications

A photopolymer comprising:

• a monomer unit of Formula I, a monomer unit of Formula II, a monomer unit of Formula III, and a monomer unit of Formula IV:
• wherein each R1 for each occurrence is independently hydrogen or methyl;
• R2 is C3-C12 cycloalkyl or C6-C12 polycyclyl;
• R3 is C1-C12 alkyl;
• and
• R4 is selected from the group consisting of
• or
• R4 is a mixture of
• wherein R5 is hydrogen or methyl,
• wherein the photopolymer has a weight average molecular weight between 10,000 to 40,000 amu, and
• wherein the monomer unit of Formula I, the monomer unit of Formula II, the monomer unit of Formula III, and the monomer unit of Formula IV are present in the photopolymer between 1-15 mol %, 35-50 mol %, 15-25 mol %, and 30-55 mol %, respectively, relative to the total moles of the monomer unit of Formula I, the monomer unit of Formula II, the monomer unit of Formula III, and the monomer unit of Formula IV.