PS emission (■) and POPOP emission (○) for 150 μm samples as a function of wt% PPO/POPOP. PS emission was obtained by measuring the excitation spectrum that yielded emission at 314 nm, then integrating the response over the region 250 nm–300 nm. POPOP emission was obtained by measuring the emission spectrum resulting from excitation at 274 nm, then integrating over the region 390 nm–500 nm.