(UL94 vertical burning test, cone calorimetry) are investigated. Alteration of chemical environment at the phosphorus atom determines various implications on burning behavior. For example, phosphorus-containing moieties promoting char generation and intumescence enhance char yields and other parameters describing flame retardant properties of phosphasilazanes in thermo-analysis as well as in cone calorimetry
There is provided a compound of the formula ##STR1## wherein m and n are integers independently selected from the group consisting of 1, 2, 3, 4, and m and m plus n equal 6. There is also provided a flame-retarded polyolefin polymer containing an effective amount of said compound.