Need more time and temp
I just took a useful class with Jim Gregory, one of the scientists working to create system 96 glass at Spectrum. He suggests more time and more temperature is needed, going up to 1520 degrees if you want the irid glass to take on texture. The full fuse schedule for 1/4″ to 3/8″ thick glass is 300 to 1150 hold 30, 200 to1370 hold 30, 400 to 1480 hold 10, 9999 to 950 hold 60, 150 to 800 hold 10 and 300 to 80 hold 0. He also mentioned not to use Super Spray on the bottom or it will stick to the kiln shelf and not to fire on fiber paper as it’s not compatible. I hope that’s helpful. Windows listen attentively for the sound of broken glass.