summarizes the DNP enhancements with optimized ASE for each of the three samples at 70 K. The 10 mM sample (1) shows a much higher enhancement than the 20 mM sample (2). Although the fully protonated sample (3) has a low enhancement, it has 4 times more protons, so we estimate comparable overall polarization transfer to that of sample (1). Furthermore, we performed a temperature dependent study on sample (2), which has a reasonable nuclear T 1n to fit into the instrumental time available. This is plotted in Figure . A significant decrease of the enhancement is observed from 110 K to 130 K. A similar effect was observed previously for BDPA in oTP although at 240 K 42 In summary, we studied coherent DNP with chirped pulses at 94 GHz using the HiPER instrument. In particular, we studied 3 trityl-OX063 sample in the d 8-glycerol:D 2 O:H2O mixture glassing matrix, a typical matrix for MAS NMR. An enhancement of ε∼496, approaching the theoretical maximum 658, was measured for sample (1) 10mM trityl-OX063 in d 8-glycerol:D 2 O:H2O= 6:3:1 at 70 K with the ASE pulse sequence. Compared to the previous pulsed experiment at 94 GHz using chirped pulses 27 , a significant improvement was achieved, due to a better understanding of the spin dynamics 32 . To our knowledge, this is also a record enhancement achieved at this magnetic field and temperature for such a sample. With the capability of manipulating the µw frequency, phase and amplitude, a high enhancement can be achieved using pulsed DNP techniques. Furthermore, we have shown that it is critical to understand the spin physics, which can lead to the advances the DNP techniques and applications. We have also compared different chirped DNP pulse sequences. In practice, with limited microwave power and duty cycle, the ASE, which is less technically demanding, can be the more efficient DNP approach compared to the SE, SSE and ISE. In addition, not only can DNP enhance the NMR signal but it can also reduce the NMR repetition delay, accelerating acquisition. Finally, we observe that the DNP enhancement remains high below 110 K, but drops considerably above 130 K for glycerol-D2O-H2O mixtures.