The H-1 and C-13 n.m.r. analysis of the sediments derived from visbrok
en short residues (150-degrees-C+) obtained at different severity leve
ls is reported. The nature of sediments and structural changes during
visbreaking and on storage at ambient conditions are related to the pr
ocessing characteristics of the residual fuel oils. The possible relat
ionship between storage stability and processing conditions is also di
scussed.