Abstract
Silicone-coated polycarbonate was photochemically modified into SiO2 by a 157 nm fluorine laser for
developing an automobile resin window. Even though this product has been globally certified as a
standard for scratch resistance, cracking was caused under a heat resistance test, and it was also found
for more severe practical uses. To suppress the cracking under a heat resistance test, we successfully
employed a steel-wool rubbing treatment to release the stress generated in the SiO2 modified layer and
maintained the optical transparency. In the treatment, the 2 N/cm2 load during the rubbing reached its
upper limit. Sandblasting and shot peening treatments were also used for comparison, but they did not
suppress the cracking.
