Abstract: The present invention relates to an optically transparent glass foam or glass-ceramic foam as well as to a method for the production of an optically transparent glass foam or glass-ceramic foam. A method is described for the production of optically transparent foams, wherein the following steps are conducted: a) Mixing of pre-ceramic Si polymer, glass powder and glass converter; b) Heating of the mixture to a temperature below the decomposition temperature of the pre-ceramic Si polymer with the formation of a foam; c) Heating the obtained foam to a temperature above the decomposition temperature of the pre-ceramic Si polymer; d) Heating the obtained product to a temperature between 700° C. and 1400° C. with the formation of glass; and e) Cooling the thus-obtained product to ambient temperature.