We present preliminary results derived from low spectral resolution infrared spectra of the comet impact sites onto Jupiter. Fragments W/K were tracked several days after the collision at the SAO 6m-telescope on July 22 and 27. A systematic increase of the spectral radiance is observed for fragment W/K spectra as compared to undisturbed region spectra. This change is interpreted as the evidence for a stratospheric haze produced by the collision. From the spectral shape of this relative increase, the albedo of the haze can reach values as low as 0.06 but is constrained between 0.13 and 0.15 if the spot size is 3″. No stringent constraint is obtained for the altitude of this haze even if a 5--50 mbar level seems to be possibly the best estimate. The particles in the haze should play a significant role in the thermal balance over impact sites. The fragments W/K spectra between July 22 and July 27 show a high stability of the haze between both dates. ¿ American Geophysical Union 1995