There is the method to form microscopic roughness on the surface of a sample in order that a film or adhesive is hard to
peel off, but it is unsuitable to optical material surfaces. We, thus, demonstrated the undamaged surface of the optical
material on which the coating agent or adhesive was applied by chemically incorporating the functional groups. Many
thin films are deposited, but most of them come off if wiped. Then, hydrophilic groups (-OH) were incorporated on the
sample surface beforehand, and photo-adhesion or coating was carried out. The sample surface was firstly treated by
discharge plasma for promoting efficiency of hydroxyl group substitution, and hydroxyl groups were incorporated on the
modified side in water ambient when the material temporarily maintained high wettability; as a result, the adhesion or
coating and the modified side were united persistently. The contact angle with water of fused silica is 40 degrees; that
of sapphire is 72 degrees; that of BK7 glass is 31 degrees. When those surfaces were irradiated by glow discharge
plasma of DC pole sputtering system for five minutes, all of the surfaces dropped to five degrees. Under this condition,
silicone oil was applied on each pretreated sample surface and irradiated with excimer lamp light (172nm) for 60 minutes.
The adhesive strength of the silica glass plates with plasma pretreatment improved to 25M pascal when compared with
that of the silica glass plates without pretreatment, which was 18M paschal.