To exploit the enormous potential transport capacity of optical fibers it will be necessary to replace many of the functions that today are implemented electronically with optical technology. These optical realizations often call for optical modulators and switches, sometimes integrated with other optical components. Polymeric integrated optical circuits hold the promise of high performance paired with low cost. The static and dynamic properties of an exploratory polymeric optochip with several Mach-Zehnder interferometers were measured. It was found that the insertion loss for butt coupling to standard fibers is relatively high and that it increases drastically but reversibly when the chip is illuminated with white light. In addition, the required bias voltages drift away slowly when the device is either subjected to laser light or connected to a voltage. Nevertheless, if certain precautions are taken, the Mach-Zehnder interferometers are well suited for switching and modulation applications. Newer polymers and lens coupling will yield lower losses and improved stability.