Compositions obtained by mixing at least one oligomer A1 which is obtained by the copolymerization of at least two monomers functionalized by diol functions with at least one second monomer, and at least one compound A2 comprising at least two boronic ester functions. They have rheological properties which vary significantly depending on the proportion of the compounds A1 and A2 used. Composition obtained by mixing at least one lubricating oil with such a composition of associative and exchangeable polymers, and use of this composition to lubricate a mechanical part.