Coherent Hyper-Raman scattering from hot polaritons gives conspicuous advantages with respect to thermal Hyper-Raman scattering. It allows a precise study of polar modes in liquids and amorphous materials, where they are forbidden in Raman scattering. We give a classical theory for this nonlinear process and the results are applied to the study of the polariton at 1065 cm−1 in amorphous quartz. The experimental data, having a precision two orders of magnitude better than in previous studies, show that the polaritons propagate in the glass with a well-defined wave vector. The dispersion curve of the polariton and its width in the wave vector space can be described by means of a multioscillator model taking into account the inhomogenous width of the levels originated from disorder.