Two-component simultaneous interpenetrating networks (IPN) of the poly(4＇-[[2-(methylacryloxy)ethyl]ethylamino]-4-nitroazobenzene-co-methyl methacrylate) (PDR1MA-co-MMA)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) system, the PDR1MA/PPO system and 4＇-[[2-(acetoxy)ethyl]ethylamino]-4-nitroazo benzene (ACDR1) doped MMA/PPO system were synthesized and characterized. As studied by differential scanning calorimetry (DSC) the full IPNs of the PDR1MA-co-MMA/PPO system and the PDR1MA/PPO system showed a single T-g varying with the PPO composition. A single-phase morphology of the full IPNs was also indicated by scanning electron microscopy(SEM). Transparent films were cast onto clean microscopic glass slides and poled at 190 degrees C for 1 h. The UV-VIS absorption spectra of the three IPN systems before and after curing and corona poling showed a shift in the maximum absorption due to the induced alignment of the nonlinear optical chromophores in the IPN systems. The absorption intensity of the full IPNs remained same after heating at 120 degrees C for 72 h, indicating that the electric field-induced alignment is stable in the full IPN materials. Preliminary second harmonic generation (SHG) data on these IPNs are presented.