We have applied electric‐field‐induced optical second‐harmonic generation to measure the distribution of chromophore sites in a dye‐doped polymer [disperse red 1 in poly (methyl methacrylate)] in terms of the standard &agr; and &bgr; parameter, that is, the decay rate and the breadth parameter. These parameters have been measured from 100 to 430 K and are modeled with a smooth function over that temperature range. Over a narrow region of temperature where second‐harmonic data from other groups exist, we find that our temperature dependence of &bgr; is in excellent agreement with these other experiments. In principle, our method can be applied to any glassy polymer to characterize the temperature dependence of the distribution of nonlinear‐optical dye sites. ©1995 American Institute of Physics.