Single‐beamZ‐scan experiments have been used to measure the two‐photon absorption coefficient &bgr; and bound electronic nonlinear refractive index &ggr; of composites of InP nanocrystals grown in 40 and 150 A˚ Vycor porous glass. These materials were also studied with two‐beam time‐resolvedZscans to confirm that the nonlinearities are instantaneous with respect to the ∼100 ps pulses used. The magnitudes of the nonlinearities in the 150 A˚ sample are found to be similar to those of bulk InP when scaled by the volume fraction of deposited material. For the 40 A˚ sample the ratio &ggr;/&bgr; is enhanced by a factor of fourteen compared to bulk InP. ©1995 American Institute of Physics.