in order to obtain a self-contained set of time evolution equations. Doi and Ohta postulated the following closure approximation and verified its accuracy. Using definition (1.2b), the convective time evolution of the anisotropy q takes the form As for the relaxation in the Doi-Ohta model, the relaxation of the state variables can be written in a generalized form In order to specify the empirical interface relaxation times τ$_{do}$$_{,}$$_{1}$ and τ$_{do}$$_{,}$$_{2}$ , assumptions on the appropriate interface relaxation mechanisms must be made. Finally, the full set of time evolution equations for the configurational variables Q and q , together with the equations for the hydrodynamic variables ρ , g and ϵ has been formulated within the GENERIC formalism [33], which for the stress tensor gives where τ is the viscous stress tensor. Although very crude, the ability of the Doi-Ohta model to connect the morphology of the system to its macroscopic behavior, through the above given set of rheological constitutive equations, is very appealing for different theoretical and technological purposes. The model and its variants have been used to analyze multiphase flow of polymers, as well as simple fluids undergoing spinodal decomposition [7, 33–40]. However, the need for explicit assump- tions of the interfacial relaxation mechanisms and the appropriate relaxation times, which depend in an unknown manner on the underlying morphology, makes it difficult for wide and easy use. Therefore, in this paper we concentrate on relating the macroscopic Doi-Ohta model to the underlying morphology, described by the more detailed Cahn-Hilliard model. 5 Σ = − τ − σ ( q − 2 3 Q 1 ) − p 1 , (1.8) ∂Q ∂t ∣ relaxation = − 1 τ$_{do}$$_{,}$$_{1}$ Q, (1.7a) ∂ q ∂t ∣ relaxation = − 1 τ$_{do}$$_{,}$$_{2}$ q . (1.7b) ∂ q ∂t ∣ convection = − ( ∇ v ) · q − q · ( ∇ v ) T − 1 3 Q ˙ γ − v · ∇ q + 1 3 1 ( ∇ v ) : q + [ q + 1 9 Q 1 ] Tr ( ∇ v ) + 1 Q ( q + 1 3 Q 1 ) ( q + 1 3 Q 1 ) : ( ∇ v ) . (1.6) nnnn : ( ∇ v ) T = 1 Q nn nn : ( ∇ v ) T (1.5)