Patent ID: 6869981

Claim:
An optical fiber coating comprising: a radiation curable composition which comprises a reactive monomer and a photoinitiator selected from the group consisting of ketones and phosphine oxides; said composition selected such that the Young's modulus of said coating is less than about 0.9 MPa, and a Chang viscoelastic window of said composition when cured exhibits at least one set of coordinates, the coordinates are in terms of the log of viscous shear modulus (G″) and the elastic shear modulus (G′) in the units of Pascals, which lies within at least one of the following windows defined by the following sets of window coordinates: (1) (about 3.000, about 4.480), (about 3.000, about 3.000), (6.000, about 4.480), and (about 6.000, about 3.000); (2) (greater than about 3.840, about 5.180), (greater than about 3.840, about 4.480), (about 6.000, about 5.180), and (about 6.000, about 4.480); (3) (about 5.112, about 6.000), (about 5.112, about 5.180), (about 6.000, about 6.000), and (about 6.000, about 5.180); (4) (about 4.530, about 5.604), (about 4.530, about 5.180), (about 5.112, about 5.604), and (about 5.112, about 5.180); and (5) (about 4.530, about 6.000), (about 4.530, about 5.729), (about 5.112, about 6.000), and (about 5.112, 5.729).