A dynamic model of the asymmetric Ising glass is presented: an Ising model with antiferromagnetbonds, −J−J, and ferromagnetic bonds, +J+J, with probabilities qq and 1−q1−q. The dynamics is introduced by changing the arrangement of the antiferromagnetic bonds after nn Monte Carlo steps but keeping the same value of qq and spin configuration. In the region where there is a second order transition between the ferromagnetic and paramagnetic states at Tc(q)Tc(q) for q<q0q<q0, the dynamic behavior follows that expected for motional narrowing and reverts to the static behavior only for large nn. There is a different dynamic behavior for q>q0q>q0 where there is a first order transitionbetween the ferromagnetic and spin glass states where it shows no effects of motional narrowing. The implications of this are discussed. This model is devised to explain the properties of doped ZnO where the magnetization is reduced when the exchange interactions change with time.