Pseudostable bubbles

The evolution of spherically symmetric unstable scalar field configurations (''bubbles'') is examined for both symmetric and asymmetric double-well potentials. Bubbles with initial static energies E0 approx-lt Ecrit, where Ecrit is some critical value, shrink in a time scale determined by their linear dimension or ''radius.'' Bubbles with E0 approx-gt Ecrit evolve into time-dependent, localized configurations which are very long-lived compared to characteristic time scales in the models examined. The stability of these configurations is investigated and possible applications are briefly discussed