Two pyrenyl Schiff base derivatives with π conjugated
structures
(
B2
and
B3
) were designed and synthesized.
Then,
B2
and
B3
were added into polyurethane
to obtain doped and bonded polyurethane nonlinear optical materials
(
B2
/PU and
B3
/PU), respectively. The synthesized
B2
,
B3
, and polyurethane nonlinear optical materials
were tested by a nanosecond (ns) and picosecond (ps) pulse
Z
-scan at a 532 nm wavelength. Due to the two-photon absorption-induced
excited state absorption (TPA-ESA),
B2
,
B3
, and polyurethane nonlinear optical materials show reverse saturable
absorption (RSA). From a quantum chemistry calculation, it can be
concluded that the RSA of
B2
and
B3
comes
from the large π conjugated system and intramolecular charge
transfer. Furthermore,
B2
,
B3
, and the polyurethane
nonlinear optical materials show good optical limiting.
B2
/PU and
B3
/PU not only have excellent nonlinear optical
properties but also have good transmittance, thermal stability, and
processability of polyurethane materials. The combination of pyrenyl
Schiff base derivatives and polyurethane materials greatly improves
the application of nonlinear small molecules in the field of optical
limiting and all-optical switching.