Time profiles of the elastically scattered and stimulated Raman scattered radiation from single ethanol droplets illuminated by 100-psec mode-locked pulses were measured with a streak camera. The Q factor of the droplet, which acts as an optical cavity, was deduced from the decay time of the internally trapped radiation. Based on the intensity dependence of time profiles, it is also deduced that the photon lifetime is limited by the depletion of the internal intensity in generating nonlinear-optical radiation.