This paper is concerned with a system of nonlinear partial differentia
l equations, in short, the coupled Cahn-Hilliard equations, which cons
ists of a fourth order quasilinear parabolic equation and a second ord
er quasilinear parabolic equation. This system was recently derived by
Penrose and Fife and also by Alt and Pawlow to describe the nonisothe
rmal phase separation of a two-component system. The global existence
and uniqueness of classical solutions is proved. The results about the
asymptotic behavior, as time goes to infinity, of solution and about
the existence and multiplicity of solutions to the corresponding stati
onary problem, which is a nonlinear boundary value problem involving n
onlocal term and constraints, are also obtained.