ABSTRACT: Physical properties deduced from OH flux density and circumstellar envelope expansion velocity are studied in a statistical sense for a sample of about 140 OH/IR stars close to the Galactic Center (GC). The sample is confined to an area on the sky of about 1.5 square degrees roughly centered on the GC and the 3 sigma sensitivity of the survey is about 60 mJy (Lindqvist et al., 1992). The distribution of the expansion velocities shows an asymmetric shape with a much steeper gradient on the high v_exp side than on the low v_exp side. It has a median value of about 18 km s-1 whereas OH/IR stars elsewhere in the Galaxy show significantly lower average expansion velocities. OH/IR stars from all parts of the Galaxy show a strong anti-correlation between expansion velocity and Galactic latitude. Thus expansion velocity is correlated with age and therefore with mass of the central star. However, close to the GC the effect of higher metallicity probably plays an important r\ole in determining the expansion velocity. The flux density distributions for GC OH/IR stars with expansion velocities smaller than (Group I) and larger than 18 km s-1 (Group II) are significantly different. Group I contains stars with higher flux densities than Group II does. Although Group I has a more extended volume density distribution than Group II this fact alone probably cannot explain the difference in their flux densities and a real difference in their OH luminosity functions has to be invoked. The dependence of mass loss rate on OH flux density and v_exp is discussed. An upper limit of the mass loss rate for the GC OH/IR stars is about 5 * 10-5 \rmMo yr-1 using the formula by Baud & Habing (1983).