This document summarizes research on increasing the switching speed of silica-on-silicon optical waveguide devices using thermo-optic effects. The devices are based on Mach-Zehnder interferometer structures with thin film titanium heaters deposited on one arm to induce a phase shift. Initial testing achieved a switching speed of 2.0 microseconds. Faster switching was achieved by applying higher driving voltages to increase heat and thus more rapidly change the refractive index. This "overdriven" approach reduced the switching time to around 0.5 microseconds, a three-fold increase. Further optimization of pulse shapes and directional coupler designs could improve performance for applications in optical communication networks.