Novel composite materials are synthesized by incorporating N-acryloylmorpholine (ACMO) in highly concentrated phenanthrenequinone (PQ) doped poly(methyl methacrylate) (PMMA). The photosensitizer concentration of PQ was increased from 0.7 wt. % to 1.8 wt. %. The doping of ACMO component results in a higher diffraction efficiency and photosensitivity than a typical PQ/PMMA system. The enhanced performance of the material may stem from the ACMO molecules, which might open a new route for improving the holographic performance of the PQ/PMMA photopolymer.