The optical recording properties such as erase speed, lifetime of written spots, maximum number of write/erase cycling of In47Se53 and In47Se51Pb2 thin films are reported. The factors whiCA influence the erase speed and stability of the written spots are discussed based on the theory of glass forming ability (GFA). It is found that the glass transition temperature Tand the reduced temperature Tg/Tm can be used to estimate the stability and erase speed or the written spots respectively. Since the elements with high Tm such as Fe, Co, Ni and A.1 possess relatively high Tg and small Tg/Tm, it is expected that the introduction of these elements into phase change optical recording materials will improve both the erase speed and stability significantly. The role of Pb on the erase speed and stability of phase change optical recording materials is similar to :hat of Tl. Its Tg/Tm value is smaller than those of In and Se, but its T is lower than those of In and Se. Therefore, the introduction of Pb into In-Se alloys will improve the erase speed and decrease the stability.