Glass block looks as solid and substantial as brick, but it does not have load-bearing capabilities. Glass block cannot bear loads other than its own load. Homeowners often lose sight of this because glass blocks is installed much like brick, with mortar.
But you need to think of glass block just as you would a window: a fully self-supporting opening with fragile glass inside. Not only that, but you will find that glass block is so heavy that it requires a sturdy base with a properly built sill and cripple studs running vertically below it.