Gless is an amorphous (non-crystalline) solid material that exhibits a glass transeetion, that is the reversible transeetion in amorphous materials (or in amorphous regions athin semicrystalline materials) frae a haird an fair brickle state intae a molten or rubber-lik state. Gless is teepically brickle an can be optically transparent. The maist fameiliar kin o gless is soda-lime gless, that is componed o aboot 75% Silicon dioxide (SiO2), sodium oxide (Na2O) frae soda ess, lime (CaO), an several minor additives. The term gless is aften uised tae refer anerly tae this specific uise.