Keep an eye on it--glass is worse than something like a nail because it may cut several threads in the casing rather than just poking through. Over time it can work into a larger hole.
You can also "boot" the tire with a piece of almost anything, inside the casing between the tire and tube. The traditional roadside boot is a dollar bill (strong, durable and only costs a buck), but I've seen people use leather, fabric and a piece cut from a mountain bike shoe (would have been cheaper to use the dollar...). I've also used that long, useless oval patch that comes with some tire repair kits--just roughen the inside of the tire and glue it on.