No, glass is definitely recycled in the true sense at least some of the time. The key word to look for when researching this is "cullet": crushed glass used as a furnace input.
e.g. Here, http://uk.saint-gobain-glass.com/trade-customers/float-glass... : "SGG UK also utilises, on average, 30% recycled glass (cullet) in the batch, which has the additional benefit of lowering the melting point of the batch, resulting in a more efficient process."