The invention relates to the use of specific organopolysilazanes as an encapsulation material for light emitting diodes (LED). The organopolysilazane polymers act as insulating filling materials and are stable over temperature and over exposure to ambient UV radiation. The encapsulating material has good thermal stability against discoloration to yellow by aging even at high temperatures which is a key factor for the long lifetime of an LED encapsulant and the LED performance.