A.  EXAMPLES OF OPTICAL MICROSCOPY IMAGES OF VITRIFIED SAMPLE

TRANSMISSION OPTICAL MICROGRAPHS OF ARBITRARILY BROKEN VITROUS SAMPLE REVEALS CROSS SECTIONAL AREA 
TUNNELS VIEWED THROUGH THE SILICA GLASS  END ON CROSS SECTIONAL SURFACE

PHOTO 1 FAR VIEW (OBSERVABLE MEANDER  PATTERN ETCHED IN DEPTH OF AEROGEL)
PHOTO 2 CLOSE UP (OBSERVABLE MEANDER PATTERN)
PHOTO 3 CLOSE UP (FOCUS ON TUNNEL ENTRANCES)

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B. EXAMPLES OF SEM IMAGING OF VITRIFIED SAMPLE 

SAMPLE PROCESSED WITH A SERIES OF PARALLEL TUNNELS WAS ARBITRARILY BROKEN TO REVEAL ITS CROSS SECTION

SEM IMAGING WITH THE  SAMPLE ROTATED TO ALIGN THE e-BEAM AXIS WITH THE AXIS OF THE TUNNELS 

TILT (OUT OF PLANE) ANGLE T=73.2 DEG  TO THE SURFACE NORMAL 
ROTATIONAL (IN PLANE) ANGLE  R=15 DEG FROM AN ARBITRARY REFERENCE 

THE  PAIR ( T X R)  = (73DEG X 15 DEG) DEFINES THE TUNNEL AXIS DIRECTION 

OTHER PAIRS ( T X R )  AS  NOTED IN  FILENAMES  

PHOTOS #21 TO #26 VIEW ALONG THE TUNNEL AXIS FROM FAR AND CLOSE UP  

PHOTOS #27 AND #32 VIEW ROTATED TO REVEAL PERSPECTIVE