Freezing point temperature measuring method and temperature calibrating method in differential scanning calorimetry

A method of measuring a freezing temperature of a sample exhibiting a supercool state, using a DSC, the method comprising:

• cooling the sample and a reference material to observe solidification of the sample in a liquid state;
• monitoring, while cooling the sample and the reference material, temperature differential values between the sample and the reference material and temperature values of the sample obtained at the DSC over a period of time including a solidifying time period which begins with an initiation of solidification of the sample in the liquid state and ends with a completion of solidification thereof;
• identifying a range of the temperature differential values which defines a state of the sample in which latent heat from the sample substantially offsets cooling of the sample;
• and
• determining the freezing temperature from a temperature value of the sample corresponding to an intersection between an imaginary line tangential to at least a part of the temperature differential values monitored within the range and an imaginary line tangential to at least a part of the temperature differential values monitored outside the solidifying time period.

A method of measuring a freezing temperature of a sample exhibiting a supercool state, using a DSC, the method comprising:

• cooling the sample to solidify the sample in a liquid state;
• monitoring, while cooling the sample, temperature values of the sample obtained at the DSC over a period of time including a solidifying time period which begins with an initiation of solidification of the sample in the liquid state and ends with a completion of solidification thereof;
• identifying a range of the temperature values which defines a state of the sample in which latent heat from the sample substantially offsets cooling of the sample;
• and
• determining the freezing temperature from a temperature value of the sample corresponding to an intersection between an imaginary line tangential to at least a part of the temperature values monitored within the range and an imaginary line tangential to at least a part of the temperature values monitored prior to the solidifying time period.

A method of measuring a freezing temperature of a sample exhibiting a supercool state, using a DSC, the method comprising:

• cooling the sample and a reference material to observe solidification of the sample in a liquid state;
• monitoring, while cooling the sample and the reference material, temperature differential values between the sample and the reference material and temperature values of the sample obtained at the DSC over a period of time including a solidifying time period which begins with an initiation of solidification of the sample in the liquid state and ends with a completion of solidification thereof;
• identifying a range of the temperature differential values which defines a state of the sample in which latent heat from the sample substantially offsets cooling of the sample;
• using at least one temperature differential value and a corresponding temperature value within the range to derive a function of the temperature differential values and the temperature values within the range, wherein the function includes a thermal resistance between the sample and a temperature measuring point at the DSC for the sample;
• and
• determining the freezing temperature from a temperature value of the sample corresponding to an intersection between a line representative of the function and an imaginary line tangential to at least a part of the temperature differential values monitored outside the solidifying time period.

A method of measuring a freezing temperature of a sample exhibiting a supercool state, using a DSC, the method comprising:

• cooling the sample and a reference material to observe solidification of the sample in a liquid state
• monitoring, while cooling the sample and the reference material, temperature differential values between the sample and the reference material and temperature values of the sample obtained at the DSC over a period of time including a solidifying time period which begins with an initiation of solidification of the sample in the liquid state and ends with a completion of solidification thereof;
• modifying the temperature values by adding thereto corresponding temperature differential values multiplied by a known thermal resistance between the sample and a temperature measuring point at the DSC for the sample;
• identifying a range of the modified temperature values which takes a constant temperature value;
• and
• determining the freezing point from the constant temperature value.