Radiation curable compositions for coating optical fiber

A method for producing a coated optical fiber comprising the steps of:

• (a) drawing a glass optical fiber through a draw tower;
• (b) applying a primary coating composition onto the surface of the glass optical fiber;
• (c) optionally, imparting a dose of UV light to at least partially cure said primary coating composition;
• (d) applying a secondary coating composition to the primary coating composition;
• (e) exposing the primary coating composition and the secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of said primary coating composition and said secondary coating composition, to form a cured primary coating on the surface of the optical fiber, and a cured secondary coating on the surface of the cured primary coating;
• wherein at least one of the primary coating composition or the secondary coating composition comprises a reactive oligomer comprising an average of at least one polymerizable group;
• a monomer comprising an average of at least one polymerizable group;
• and
• a photoinitiator;
• wherein the photoinitiator possesses
• (i) a normalized rate of polymerization at 150° C. of greater than 0.5, wherein the normalized rate of polymerization at 150° C. is the maximum polymerization rate (in mmol/kg sec) of a mixture at 150° C. divided by the maximum polymerization rate of the mixture at 25° C., wherein the mixture comprises 1 part by weight of the photoinitiator and 99 parts by weight of ethoxylated nonyl-phenol acrylate, and the polymerization rate is determined via an RT-FTIR method, wherein the RT-FTIR method is conducted while employing an ATR crystal with a 60 micron film, and a Dr. Honle D-bulb with an irradiance of 20 mW/cm2;
• or
• (ii) a potential excited triplet state with an ionization potential from 3.0 electron volts (eV) to 3.90 eV, wherein the ionization potential is calculated in accordance with molecular modeling B3LYP/6-31G(d) in combination with Koopman's Theorem (IP=−ϵHOMO).