Create an env_entity_maker which spawns the glass of the type you want, and place it in the centre where you want the glass to spawn. Set the output on the glass so that when it breaks, it triggers a logic_relay (as the glass entity will be killed), set the logic_relay's output to spawn another glass through the env_entity_maker. Set the delay time on the spawn output to the time you want the glass to respawn in.
I hope that works.