an optical fiber ribbon in which a plurality of optical fibers are held in an array has a matrix material for bonding to the fibers to form the ribbon . the matrix material has certain characteristics which serve to enhance fiber access , among which are an elastic modulus from 600 to 1200 mpa at room temperature , from 100 to 280 mpa at 100 ° c ., and from 15 to 45 mpa at temperatures greater than 170 ° c . the matrix material swells in ethanol more than 15 % by volume within 20 minutes , and is virtually immune to the action of cleaning solvents . the matrix material has a surface tension of 20 - 35 mj / m 2 as do the color coding inks which identify the fibers .