Polymer-stabilized liquid crystal blue phases are promising candidates for next generation liquid crystal displays. The electro-optic Kerr effect in blue phases provides fast response times and an optically isotropic dark state, without needing any alignment layers. However, obstacles to overcome are high operation voltage, hysteresis and residual birefringence. In this work, the optics of blue phases with visible Bragg reflections are studied. For polymer-stabilized systems, it is shown that the improved performance results from suppression of electrostriction and field-induced phase transitions. In this context, a method to estimate the quality of polymer-stabilization is established. Additionally, blue phase systems with Bragg reflections in the UV range are considered. Mono-functional mesogenic monomers and non-mesogenic cross-linkers are polymerized to stabilize the blue phase, which differs from the commonly used combination of non-mesogenic mono-functional monomers and mesogenic cross-linkers. For this new blue phase system, the electro-optic performance is investigated depending on sample composition and polymerization conditions. The new system shows promising results on the route to bluephase mode display applications.