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Highlights • There are marked differences in dynamics of modified linear and cyclic carbohydrates. • A variation in the distribution of τ α between linear and cyclic compounds is observed. • The evolutions of the T g and m versus M w in both groups of materials are different. • The shape of the α -process in saccharides of the same topology doesn't change with M w. Abstract In this paper, the molecular dynamics and thermal properties of representative acetylated linear and cyclic oligosaccharides: acTRE, acRAF, acSTA, ac-α-CD, ac-β-CD, ac-γ-CD, have been investigated by using broadband dielectric spectroscopy and differential scanning calorimetry. We found that there are marked differences in the dynamics of the structural and secondary relaxation processes in both groups of materials. Just to mention a variation in the distribution of the structural relaxation times as well as different evolutions of the glass transition temperature (T g) and fragility (m) versus molecular weight (M w), which seem to be affected by the shape of the molecule, strain in the carbohydrate ring and mobility of side acetyl moieties. [ABSTRACT FROM AUTHOR]