  The gravitational-wave instability of r-modes in rapidly rotating compact
stars is believed to spin them down to angular frequencies of about a tenth of
the Kepler frequency soon after their birth in a Supernova. We point out that
the r-mode perturbation also impacts the neutrino cooling and viscosity in hot
compact stars via processes that restore weak equilibrium. We illustrate this
fact with a simple model of spin-down due to gravitational wave emission in
compact stars composed entirely of three-flavor degenerate quark matter (a
strange quark star). Non-equilibrium neutrino cooling of this oscillating fluid
matter is quantified. Our results imply that a consistent treatment of thermal
and spin-frequency evolution of a young and hot compact star is a requisite in
estimating the persistence of gravitational waves from such a source.
