The concept of self-association oligooxaethylenes (glymes) is discussed in terms of the associated mixture model with equation of state contributions [A.J. Treszczanowicz, G.C. Benson, Fluid Phase Equilib., 23 (1985) 117]. The model was applied to interpret and describe the excess thermodynamic properties of binary mixtures formed by 2,5-dioxahexane or 2,5,8-trioxanonane with n-alkane. The excesses enthalpy H E, heat capacity C p E, volume V E and isobaric thermal expansion A p E=(∂ V E/∂ T) p were used to estimate the model parameters: standard enthalpy, entropy and volume of self-association and non-specific interactions parameter. The application of the equation of state alone does not allow to describe A p E and other thermodynamic properties, unless association is taken into consideration. Calculations show the glymes to be very weakly self-associated, and characterized by the high monomer concentration in the pure state. The description of the glyme+alkane mixtures was compared with the results for relatively strong self-associated 1-alkanol mixtures. The chemical contributions to A p E and C p E for glyme mixtures have negative signs, different than those for alkanol mixtures. The association, even if it is weak, has an essential contribution to the thermodynamic properties.