It has come to our attention that customers working with certain coating systems had problems making near infrared transparencies in blue shades. They said that most of the available blue dyes were either insufficiently soluble in the coating media or unstable to the lamination process, undergoing wavelength shifts or disappearing in the heating cycle. Azo dyes were the worst because they interacted with the NIR dyes, canceling out their absorption.
Our Russian born and educated chemist, Oleg (Dr. Ponomarev) came up with an effective solution to this problem. It was a blue dye which he named after his dog, Vasya Blue, (our number 5411). Vasya Blue shows broad band absorption. l max at 620 nm, with absorptivity of 120 and quite stable to polycarbonate injection molding conditions.
