ISSN 0018-1439, High Energy Chemistry, 2006, Vol. 40, No. 3, pp. 178–181. © Pleiades Publishing, Inc., 2006.
Original Russian Text © V.V. Bivol, S.V. Robu, A.M. Prisacari, A.Yu. Meshalkin, L.A. Vlad, M.I. Karaman, 2006, published in Khimiya Vysokikh Energii, 2006, Vol. 40, No. 3,
pp. 216–219.
178
1
In the last decades, particular attention was given to
investigation of photoresist media based on carbazole-
containing polymers, such as poly-N-vinylcarbazole
(PVK); poly-N-epoxypropylcarbazole (PEPC); and
copolymers of carbazolylalkyl methacrylates (CAM)
with alkyl methacrylates, including octyl methacrylate
(OMA) [1–3], sensitized with polyhalogenated meth-
ane derivatives and other additives as activators. Photo-
sensitive layers made from these compositions make it
possible to record analog and holographic images with
high photographic characteristics. For example, as
shown in [4, 5], holographic gratings and images with
a diffraction efficiency up to 20% and a resolution of
2000 mm
–1
were obtained on the photoresist PEPC and
CAM : OMA copolymer media sensitized with tri-
iodomethane. However, two-component systems pos-
sess low photosensitivity of the order of 10
–2
J cm
–2
. To
enhance the photosensitivity of such photoresist media,
we studied in this work these photoresist materials
made from carbazolylalkyl methacrylate copolymers
and polyepoxypropylcarbazole sensitized with tri-
iodomethane or additives of indolynospirobenzopyran
photochromic materials (5–15%).
EXPERIMENTAL
Carbazolylalkyl methacrylate–octyl methacrylate
copolymers containing 60–80 mol % of CAM units
were prepared by solution polymerization in the pres-
ence of an initiator (AIBN) at a temperature of 80°C.
1
e-mail: bivol@as.md
Poly-N-epoxypropylcarbazole was synthesized by
anionic polymerization at 120°C. In all cases, the syn-
thesized polymers were purified by single or double
reprecipitation from methanol. For complete drying,
they were held in a vacuum drying oven at 50°C to a
constant weight.
Solutions (10–15%) of synthesized copolymers,
mainly CAM : OMA (60 : 40 mol %) and (80 : 20 mol %)
copolymers and PEPC, containing triiodomethane
(10 wt %) and photochromic 6'-bromo-8'-nitro-1,3,3-
trimethylindolinspirobenzpyran (BNSP) (5–15%) were
prepared in toluene or chlorobenzene.
Photopolymer layers (PPLs) were applied by cast-
ing from solutions on a flexible poly(ethylene tereph-
thalate) substrate with the use of a special meniscus
device. The layer thickness n was varied from 2 to
10 μm. To prepare thicker layers, solutions with a con-
centration higher than 15% were taken. After the stor-
age of the samples in air, the layers were additionally
dried in a vacuum drying oven at ambient temperature.
The thickness of the layers was monitored with an
MMI-4 interference microscope.
Photoresist layers were irradiated by UV light from
a PRK-4 mercury lamp (E = 4.0 J cm
–2
) and by a tung-
sten filament lamp (600 W, E = 80000 lx). Changes in
the optical density in the layers were observed both
visually or with an SF-18 spectrophotometer.
High quality holograms were obtained with a setup
based on a 1-W continuous-wave Ar ion laser and a
20-mW He–Cd laser. This equipment allowed us to
obtain high-quality holographic images with a depth
PROCESSES AND MATERIALS
FOR OPTICAL INFORMATION SYSTEMS
Study of Sensitometric and Holographic Properties of Photoresist
Media Based on Carbazole-Containing Polymers Sensitized
with Triiodomethane and Pyran Photochromic Materials
V. V. Bivol
a
,
1
S. V. Robu
b
, A. M. Prisacari
a
, A. Yu. Meshalkin
a
,
L. A. Vlad
a
, and M. I. Karaman
b
a
Optoelectronics Center, Academy of Sciences of Moldova, ul. Akademiei 1, Chisinau, MD-2028 Moldova
b
State University of Moldova, ul. Mateevich 60, Chisinau, MD-2003 Moldova
Received January 19, 2005
Abstract—Sensitometric and holographic properties of photoresist layers made from carbazolylalkyl meth-
acrylate copolymers and polyepoxypropylcarbazole sensitized with triiodomethane and, additionally, spiropy-
ran photochromic compounds were studied. It was found that the introduction of photochromic 6'-bromo-8'-
nitro-1,3,3-trimethylindolylspirobenzopyran (8–12%) into photoresist layers increased their photographic sen-
sitivity by a factor of 2.5–3 up to the values of 10
–3
–10
–4
J cm
–2
and shifted their spectral sensitivity to the blue-
green region. The feasibility of recording quality holograms in the photoresist layers using coherent He–Cd
laser light (λ = 420 nm), as well as argon laser light (λ = 490 nm), was shown. Diffraction gratings with an
efficiency of 15–20% and a resolution of 2000 mm
–1
were obtained.
DOI: 10.1134/S001814390603009X