Laser-microwave photoconductivity measurements were performed on thermally oxidized silicon wafers. Using a 830 nm laser, an almost exponential decay profile and similar effective lifetime were observed for the range of laser powers (7.5-25 W) used while the decay profile using a 910 nm laser was found to be strongly dependent on the laser power used. The 910 nm laser gave an unusual decay profile which is attributed to the presence of emitting traps located interior to the wafer at depths greater than 12 mu m from the surface.