  Amorphous materials are integral part of todays technology, they commonly are
performant and versatile in integration. Consequently, future applications
increasingly aim to harvest the potential of the amorphous state. Establishing
its structure-property relationship, however, is inherently challenging using
diffraction-based techniques yet is extremely desirable for developing advanced
functionalities. In this article, we introduce a set of transmission electron
microscopy-based techniques to locally quantify the structure of a material.
This unique approach allows to clearly identify the spatial distribution of
amorphous and crystalline regions and to quantify atomic arrangements of
amorphous regions of a representative model system. We study an ensemble of
well-defined, functionalized adamantane-type cluster molecules exhibiting
exceptionally promising nonlinear optical properties of unclear origin. The
nanoscopic structure for three model compounds ([(PhSn)4S6], [(NpSn)4S6],
[(CpSn)4S6]) correlates with their characteristic optical responses. These
results highlight the advantageous properties of amorphous molecular materials
when understanding the microscopic origin.
