This peculiar spell in Egyptian Secrets of Albertus Magnus provides two recipes for making glass soft and pliable, so that it can be rolled like fabric.
It is immediately followed by a general spell for hardening things, such as metal and (presumably) glass.
From Egyptian Secrets of Albertus Magnus, Joseph H. Peterson edition:
To Soften Glass.
Take soluble glass or verre, burn it in a retort to water, and dissolve in this same water some gum arabic; this will so soften the glass, that it may be wrapped up like a cloth.
Or, take eggs, and mix with quick lime, and put the glass therein. It becomes soft in this manner.
The grimoire Egyptian Secrets of Albertus Magnus lists this spell.
Timeline of related events
1725Publication of Egyptian Secrets of Albertus Magnus (lists this spell)
1869English-language translation of Egyptian Secrets (lists this spell)