  Using Monte Carlo simulations we study the dynamics of three-dimensional
Ising models with nearest-, next-nearest-, and four-spin (plaquette)
interactions. During coarsening, such models develop growing energy barriers,
which leads to very slow dynamics at low temperature. As already reported, the
model with only the plaquette interaction exhibits some of the features
characteristic of ordinary glasses: strong metastability of the supercooled
liquid, a weak increase of the characteristic length under cooling,
stretched-exponential relaxation and aging. The addition of two-spin
interactions, in general, destroys such behaviour: the liquid phase loses
metastability and the slow-dynamics regime terminates well below the melting
transition, which is presumably related with a certain corner-rounding
transition. However, for a particular choice of interaction constants, when the
ground state is strongly degenerate, our simulations suggest that the
slow-dynamics regime extends up to the melting transition. The analysis of
these models leads us to the conjecture that in the four-spin Ising model
domain walls lose their tension at the glassy transition and that they are
basically tensionless in the glassy phase.
