The linear dynamic moduli of a P alpha MSAN/PMMA blend have been measured d
uring spinodal decomposition and the subsequent coarsening of the co-contin
uous morphology. The feasibility of probing this morphology development by
rheological measurements has been investigated. During phase separation, th
e storage modulus shows a power law behaviour at low frequency and its valu
e decreases as time proceeds. However, effects of the dynamic measurement o
n the morphology development have been observed, even for strain amplitudes
as low as 0.01. This effect of oscillatory shear on the coarsening of a co
-continuous structure is consistent with the predictions of the Doi-Ohta th
eory.