Instrumented　indentation　was　used　to　investigate　the　proportional　relationships　among　indentation　variables　such　as　the　maximum　indentation　displacement,　contact　depth,　the　ratio　of　load　over　contact　stiffness,　and　the　ratio　of　permanent　displacement　over　the　maximum　displacement.　Material　and　indenter　were　borosilicate　K9　glass　and　a　Berkovich　indenter,　respectively.　Results　of　fused　silica　under　the　same　indenter　were　compared.　Load-displacement　curves　of　K9　glass　were　characterized　by　power-law　functions　for　both　loading　(power　exponent　of　2)　and　unloading　(power　exponent　of　1.36)　with　hardness,　elastic　modulus,　yield　stress,　and　power　strain　hardening　exponent　being　7.72,　82.8,　3.5　GPa,　and　0.6,　respectively.　Experimental　results　were　found　to　be　in　agreement　with　theoretical　prediction　and　dimensional　analysis.　The　results　calculated　from　energy-based　method　were　found　to　be　consistent　with　those　based　on　Oliver　and　Pharr＇s　method.　General　implications　of　the　scaling　relations　for　indentation　variables　were　discussed　(e.g.,　the　scaling　expressions　can　be　used　to　check　indentation　data).　(C)　2018　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE).