Since it's only a limited area to be glassed, all the glass will be accumulating dust and debris carried by weather from all around it.

This means that it won't take long for lichens to start growing, followed by grass, shrubs and small plants. Once vegetation is there, also animal can follow.

At the same time the more exposed part will be sanded by wind carried particles.

My estimate is that in 60 years you might even start to have trees and not notice much differences with the unglassed surrounding regions.

Since it's only a limited area to be glassed, all the glass will be accumulating dust and debris carried by weather from all around it.

This means that it won't take long for lichens to start growing, followed by grass, shrubs and small plants the more dust and debris will accumulate. Once vegetation is there, also animal can follow.

At the same time the more exposed part will be sanded by wind carried particles.

My estimate is that in 60 years you might even start to have trees and not notice much differences with the unglassed surrounding regions.