TRANSMITTANCE %
90°4,
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4000
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3500
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These spectra, of a piece of rolled polyester film only 1.5 mm square, were taken
with the aid of two P-E accessories: a wire-grid polarizer and a | X 4 refracting
beam condenser (see illustration). They show how polarized radiation can be used
to obtain fundamental information on even the smallest polymer samples. From
the dichroic behavior of two absorption bands, it can be seen that the polymer
chains ore preferentially aligned parallel to the machine, or rolling direction. Here's
how: the two spectra were taken with the wire grid polarizer at orientations 90°
HERE'S A NEW
DIMENSION
IN MICROANALYSIS
Our Model 62171IR Spectraphotometer lets you
work with the smallest of samples. You can
record good spectra with less than 0.1 micro-
liter of liquid—or even as little as 50 nanograms
of solid.
The unique. micro-capabilities of the Model 621
result from its fast £/4.5 optical system, folded,
compact optical path and small sample
aperture. We use aspheric optics for the most
t
1600
1400
FREQUENCY cm"!
|
1200
1000
|
800
600
400
200
apart. The relative intensities of the C=O band at 1725 cm-! and the aromatic
carbon-hydrogen bending vibration at 1500 cm-! can be used to determine the
relative orientations of the transition moments associated with these vibrations. The
1725 em! band has its maximum intensity when the polarizer is oriented to transmit radiation perpendicular to the machine direction of the film: i.e., the band
exhibits perpendicular dichroism. On the other hand, the 1500 cm-? band shows
parallel dichroism. The Model 621 makes this kind of analysis easy to do.
efficient transfer of enargy and precise imag-
ery. The shorter optical path makesit easier to
purge water vapor and carbon dioxide from
the sealed instrument.
We've designed special accessories to give you
optimum micro-performance. We offer a microcell and beam-condenser combination, an
ultra-micro 6X beam condenser, and a micro-
specular reflectance attachment. The spectra
show how a new Perkin-Elmer accessory, the
Wire Grid Polarizer, is used in conjunction with
a beam condenser to reveal orientation of the
functional groups in a polyester film.
The unique power of this instrument in the
micro-sampling range also makes it ideal for
analyzing chromatographic fractions. But it
hasn‘t been designed for microanalysis alone.
We've built in every possible convenience and
technical improvement for rapid, precise work.
You can alsa handle ordinary samples faster
and easier. The Model 621 gives you unparalleled sensitivity over its entire range.
Write for our 16-page brochure on the Model
621. We’ll also send you a brochure describing
the many accessories available. Address: Instrument Division, Perkin-Elmer Corporation,
Main Avenue, Norwalk, Conn. 06852.
723
PERKIN-ELMER
Detail of sample area showing 1x4 beam condenser (foreground) and attenuator mounted in reference beam.