As the (Ti, Nb)O, amorphous thin films cannot be prepared under a self-supported form, we have recorded the X-ray reflectivity. A new program which allows extraction of the X-ray absorption from the reflectivity is briefly described. The correction of the anomalous dispersion effect is effective, particularly near the edge within 200eV. Hence, it has allowed a comparison between the amorphous layers and the crystalline analogues for which the X-ray absorption has been recorded by transmission. In the amorphous state, the TiO, group is smaller than in the crystalline state because of the relaxation of the crystallographic constraints. The oxygen coordination octahedron is almost regular in the films. On the other hand, in both cases, an electron transfer takes place from Nb to Ti.