Flame retardant compositions

A flame retardant composition comprising:

• (a) 81 to 99.99 weight percent of a thermoplastic resin, thermoset resin, thermoplastic resin blend, or thermoset resin blend which upon burning forms a char;
• and
• (b) 0.01-19 weight percent of a silsesquioxane resin having a weight average molecular weight of greater than 300 and having the average molecular formula:
• (R3SiO1/2)a (R2SiO2/2)b (RSiO3/2)c (SiO4/2)d (RO1/2)e (OH1/2)f
• wherein each R is hydrogen, methyl, or phenyl, a and b are zero or positive numbers and the value of a+b is greater than zero, c is a positive number, d, e and f are zero or positive numbers with the provisos that the copolymer comprises at least 40 mole percent of RSiO3/2 units, the copolymer comprises less than 10 mole percent SiO4/2 units, greater than 30 mole percent of the silicon-bonded R groups are silicon-bonded phenyl groups, at least 13 mole percent of the silicon-bonded R groups are silicon-bonded hydrogen atoms, the content of silicon-bonded hydroxyl groups is equal to or less than 2 weight percent, and the content of silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy is equal to or less than 5 weight percent.