TRANSITIONS AND THE RELAXATION SPECTROGRAPH - POLY(OXYMETHYLENE)

In place of directly assaying the relative rebound height of a ball from a polymeric sample, the passage time of the ball between fixed points is used in a much more precise version of the poor man's relaxation spectrograph. Poly(oxymethylene) has a sharp transition at minus 74. 8 degree C which progressively becomes broader and moves to minus 39. 0 degree C as the polymer is pretreated at 70 degree C and exposed to 330 nm light for times up to 1038 ksec. A second transition, broad and shallow, is seen in the range 104 to 124 degree C and is unaffected by the pretreatment. This is attended by a slight decrease in density, proportional to the time held at 70 degree C, at the rate of minus 3. 54 multiplied by 10** minus **9 g/cm**3 sec.