I found a glass chest piece in the location for the first mage guild (College) quest at a place called Soarthal I think? It was hidden so you'll have to search, you could also level your smithing to 70 and make your own.
I'm not stealing, I just keep my money in other peoples wallets. 3Ds code: Patrick 1203-9229-0840, GT:CyanDoomdragon
You need to be around level 25-30 before you start finding glass armor as random loot in chests and such. If you want it earlier than that, smithing is the way to go. Just be warned that power-leveling smithing has been known to ruin the game for some people, because once you make the best armor for yourself, you no longer get that same sense of excitement & accomplishment when you find better gear in dungeons or whatever.