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We present Spitzer Space Telescope time-series photometry at 3.6 and 4.5$\mu$m of 2MASS J11193254$-$1137466AB and WISEA J114724.10$-$204021.3, twoplanetary-mass, late-type ($\sim$L7) brown dwarf members of the $\sim$10 Myrold TW Hya Association. These observations were taken in order to investigatewhether or not a tentative trend of increasing variability amplitude withdecreasing surface gravity seen for L3-L5.5 dwarfs extends to later-L spectraltypes and to explore the angular momentum evolution of low-mass objects. Weexamine each light curve for variability and find a rotation period of19.39$^{+0.33}_{-0.28}$ hours and semi-amplitudes of 0.798$^{+0.081}_{-0.083}$%at 3.6 $\mu$m and 1.108$^{+0.093}_{-0.094}$% at 4.5 $\mu$m for WISEAJ114724.10$-$204021.3. For 2MASS J11193254$-$1137466AB, we find a single periodof 3.02$^{+0.04}_{-0.03}$ hours with semi-amplitudes of0.230$^{+0.036}_{-0.035}$% at 3.6 $\mu$m and 0.453 $\pm$ 0.037% at 4.5 $\mu$m,which we find is possibly due to the rotation of one component of the binary.Combining our results with 12 other late-type L dwarfs observed with Spitzerfrom the literature, we find no significant differences between the 3.6 $\mu$mamplitudes of low surface gravity and field gravity late-type L brown dwarfs atSpitzer wavelengths, and find tentative evidence (75% confidence) of higheramplitude variability at 4.5 $\mu$m for young, late-type Ls. We also find amedian rotation period of young brown dwarfs (10-300 Myr) of $\sim$10 hr, morethan twice the value of the median rotation period of field age brown dwarfs($\sim$4 hr), a clear signature of brown dwarf rotational evolution.

Spitzer Light Curves of the Young, Planetary-Mass TW Hya Members 2MASS J11193254-1137466AB and WISEA J114724.10-204021.3